diff --git a/apps/app/auto-imports.d.ts b/apps/app/auto-imports.d.ts
index 8881070e..3666f9c9 100644
--- a/apps/app/auto-imports.d.ts
+++ b/apps/app/auto-imports.d.ts
@@ -550,12 +550,10 @@ declare module 'vue' {
     readonly templateRef: UnwrapRef<typeof import('@vueuse/core')['templateRef']>
     readonly throttledRef: UnwrapRef<typeof import('@vueuse/core')['throttledRef']>
     readonly throttledWatch: UnwrapRef<typeof import('@vueuse/core')['throttledWatch']>
-    readonly toBreadcrumbItems: UnwrapRef<typeof import('./src/composables/useBreadcrumb')['toBreadcrumbItems']>
     readonly toRaw: UnwrapRef<typeof import('vue')['toRaw']>
     readonly toReactive: UnwrapRef<typeof import('@vueuse/core')['toReactive']>
     readonly toRef: UnwrapRef<typeof import('vue')['toRef']>
     readonly toRefs: UnwrapRef<typeof import('vue')['toRefs']>
-    readonly toV2NavGroups: UnwrapRef<typeof import('./src/composables/useV2Nav')['toV2NavGroups']>
     readonly toValue: UnwrapRef<typeof import('vue')['toValue']>
     readonly triggerRef: UnwrapRef<typeof import('vue')['triggerRef']>
     readonly tryOnBeforeMount: UnwrapRef<typeof import('@vueuse/core')['tryOnBeforeMount']>
@@ -670,7 +668,6 @@ declare module 'vue' {
     readonly useMouseInElement: UnwrapRef<typeof import('@vueuse/core')['useMouseInElement']>
     readonly useMousePressed: UnwrapRef<typeof import('@vueuse/core')['useMousePressed']>
     readonly useMutationObserver: UnwrapRef<typeof import('@vueuse/core')['useMutationObserver']>
-    readonly useNavBreadcrumb: UnwrapRef<typeof import('./src/composables/useBreadcrumb')['useNavBreadcrumb']>
     readonly useNavigatorLanguage: UnwrapRef<typeof import('@vueuse/core')['useNavigatorLanguage']>
     readonly useNetwork: UnwrapRef<typeof import('@vueuse/core')['useNetwork']>
     readonly useNow: UnwrapRef<typeof import('@vueuse/core')['useNow']>
@@ -743,7 +740,6 @@ declare module 'vue' {
     readonly useTrunc: UnwrapRef<typeof import('@vueuse/math')['useTrunc']>
     readonly useUrlSearchParams: UnwrapRef<typeof import('@vueuse/core')['useUrlSearchParams']>
     readonly useUserMedia: UnwrapRef<typeof import('@vueuse/core')['useUserMedia']>
-    readonly useV2Nav: UnwrapRef<typeof import('./src/composables/useV2Nav')['useV2Nav']>
     readonly useVModel: UnwrapRef<typeof import('@vueuse/core')['useVModel']>
     readonly useVModels: UnwrapRef<typeof import('@vueuse/core')['useVModels']>
     readonly useVibrate: UnwrapRef<typeof import('@vueuse/core')['useVibrate']>
diff --git a/apps/app/src/components-v2/layout/AppBreadcrumb.vue b/apps/app/src/components-v2/layout/AppBreadcrumb.vue
index 26af0ab0..fac871cf 100644
--- a/apps/app/src/components-v2/layout/AppBreadcrumb.vue
+++ b/apps/app/src/components-v2/layout/AppBreadcrumb.vue
@@ -2,21 +2,16 @@
 /**
  * AppBreadcrumb — layout primitive per RFC-WS-PRIMEVUE-PLAN-2-5 AD-2.5-B1.
  *
- * Consumes `useNavBreadcrumb` (registry-driven; data derives from
+ * Consumes `useBreadcrumb` (registry-driven; data derives from
  * APP_NAVIGATION + the current route name). Wired into AppTopbar in P5
- * (RFC §5.2 Fix 2) — standalone in P1.
- *
- * Naming note: imports `useNavBreadcrumb` (not the literal `useBreadcrumb`
- * the AD specifies) because the legacy meta-based `useBreadcrumb` is still
- * consumed by AppTopbar; P1 may not touch AppTopbar (P4–P6 scope). P4
- * retires the legacy API and renames `useNavBreadcrumb` → `useBreadcrumb`.
+ * (RFC §5.2 Fix 2).
  */
 
 import { computed } from 'vue'
 import Breadcrumb from 'primevue/breadcrumb'
-import { useNavBreadcrumb } from '@/composables/useBreadcrumb'
+import { useBreadcrumb } from '@/composables/useBreadcrumb'
 
-const crumbs = useNavBreadcrumb()
+const crumbs = useBreadcrumb()
 
 const items = computed(() =>
   crumbs.value.map(c => ({
diff --git a/apps/app/src/components-v2/layout/AppSidebar.vue b/apps/app/src/components-v2/layout/AppSidebar.vue
index 355a2c92..5607e1a3 100644
--- a/apps/app/src/components-v2/layout/AppSidebar.vue
+++ b/apps/app/src/components-v2/layout/AppSidebar.vue
@@ -25,6 +25,13 @@
  * source), but @/config/navigation is the unclassified central registry
  * and is consumed in-place by SidebarNav.
  *
+ * Vertical order (Plan 2.5 P5 Fix 3): SidebarHeader → SidebarNav →
+ * WorkspaceSwitcher (bottom-anchored). The bottom anchoring is achieved
+ * by SidebarNav's root <nav class="flex-1 ..."> filling all available
+ * space inside this aside's flex-col column — no separate spacer element
+ * is needed (two flex-1 siblings would split the column 50/50 and
+ * compress the nav).
+ *
  * Deliberate simplification: crewli-starter's bespoke Teleport tooltip (shown in
  * collapsed mode for nav items) is NOT ported here. SidebarNav already provides
  * native `:title` tooltips in collapsed mode, which is functionally equivalent
diff --git a/apps/app/src/components-v2/layout/AppTopbar.vue b/apps/app/src/components-v2/layout/AppTopbar.vue
index 729e0c93..4a490b8c 100644
--- a/apps/app/src/components-v2/layout/AppTopbar.vue
+++ b/apps/app/src/components-v2/layout/AppTopbar.vue
@@ -4,8 +4,9 @@
  *
  * Wiring:
  *  - Hamburger → shell.setMobileOpen(true) (mobile only, lg:hidden)
- *  - Brand: static mark + wordmark (Tailwind from .topbar-brand/.mark/.wordmark)
- *  - Breadcrumb: PrimeVue <Breadcrumb> fed from useBreadcrumb(), route-driven
+ *  - Breadcrumb: <AppBreadcrumb /> primitive (registry-driven via APP_NAVIGATION).
+ *    Brand block was removed in Plan 2.5 P5 (RFC §5.1 Fix 1) — sidebar
+ *    owns Crewli identity.
  *  - Mobile workspace button: org gradient via computeOrgGradient() + initials
  *  - Search: static InputText with ⌘K hint (no backend, chrome only)
  *  - Density toggle: shell.setDensity() with flipped value
@@ -30,64 +31,29 @@
  *
  * Styling: crewli-starter CSS translated to Tailwind inline.
  * <style scoped> used only for:
- *   1. topbar-mark-shadow — inset box-shadow (no Tailwind utility at this granularity, RFC §7.4)
- *   2. ws-mobile-btn-shadow — same inset shadow justification
+ *   1. ws-mobile-btn-shadow — inset box-shadow (no Tailwind utility at this
+ *      granularity, RFC §7.4)
  */
 
 import Avatar from 'primevue/avatar'
-import Breadcrumb from 'primevue/breadcrumb'
 import InputText from 'primevue/inputtext'
 import Menubar from 'primevue/menubar'
 import Menu from 'primevue/menu'
 import OverlayBadge from 'primevue/overlaybadge'
 import Popover from 'primevue/popover'
 import { computed, ref } from 'vue'
-import { useRouter } from 'vue-router'
 import type { MenuItem } from 'primevue/menuitem'
 import Icon from '@/components/Icon.vue'
-import { useBreadcrumb } from '@/composables/useBreadcrumb'
 import { useAuthStore } from '@/stores/useAuthStore'
 import { useShellUiStore } from '@/stores/useShellUiStore'
 import { computeOrgGradient } from '@/utils/v2/gradient'
 
 // ---------------------------------------------------------------------------
-// Stores / router
+// Stores
 // ---------------------------------------------------------------------------
 
 const shell = useShellUiStore()
 const authStore = useAuthStore()
-const router = useRouter()
-
-// ---------------------------------------------------------------------------
-// Breadcrumb — route-driven via useBreadcrumb()
-// ---------------------------------------------------------------------------
-
-const { items: breadcrumbItems } = useBreadcrumb()
-
-/**
- * Map BreadcrumbItem[] → PrimeVue MenuItem[].
- *
- * The installed PrimeVue Breadcrumb (BreadcrumbItem.vue) renders
- * `<a :href="item.url || '#'">` and calls `item.command` on click.
- * It does NOT honour a `route` key — router-link is never invoked.
- *
- * Fix: non-last items navigate via `command: () => router.push(item.to)` (client-side,
- * no full reload, no href="#"). Last/current item has no `to` from useBreadcrumb()
- * → no command → non-interactive.
- */
-const breadcrumbModel = computed<MenuItem[]>(() =>
-  breadcrumbItems.value.map(item => {
-    const base: MenuItem = { label: item.label }
-
-    if (item.to !== undefined) {
-      base.command = () => {
-        router.push(item.to!)
-      }
-    }
-
-    return base
-  }),
-)
 
 // ---------------------------------------------------------------------------
 // User initials derived from full_name
@@ -278,42 +244,16 @@ const userMenuItems = computed<MenuItem[]>(() => [
         </button>
 
         <!--
-          Brand — hidden on mobile, shown >=lg.
-          .topbar-brand: display none default, display inline-flex >=lg
-          .mark: 28x28, rounded-lg, gradient bg, white text, font-bold 13px
-          .wordmark: font-bold 16px, tracking-tight
-        -->
-        <div class="hidden lg:inline-flex items-center gap-2">
-          <!--
-            Topbar mark — dynamic gradient cannot be a static Tailwind class.
-            Inline style justified (RFC §7.4). Box-shadow via scoped CSS
-            (inset-shadow has no Tailwind utility at this granularity).
-          -->
-          <div
-            class="topbar-mark-shadow inline-flex h-7 w-7 flex-shrink-0 items-center justify-center rounded-lg text-[13px] font-bold text-white"
-            style="background: linear-gradient(135deg, var(--p-primary-500, #0d9488), var(--p-primary-700, #0f766e))"
-            aria-hidden="true"
-          >
-            C
-          </div>
-          <span class="text-[16px] font-bold tracking-[-0.01em] text-[var(--p-text-color)]">
-            Crewli
-          </span>
-        </div>
-
-        <!--
-          Breadcrumb — PrimeVue Breadcrumb, route-driven.
-          .breadcrumb: flex, items-center, gap-[6px], text-[13px], color fg-muted, flex-wrap nowrap, overflow-hidden
-          Hidden on mobile per crewli-starter (<768px: display:none!important)
+          Breadcrumb — registry-driven via <AppBreadcrumb /> (consumes
+          APP_NAVIGATION). The Crewli brand block was removed in Plan 2.5
+          P5 (RFC §5.1 Fix 1); the sidebar owns the Crewli identity now.
+          Hidden on mobile per crewli-starter (<768px: display:none!important).
         -->
         <nav
           class="hidden lg:flex items-center"
           aria-label="Breadcrumb"
         >
-          <Breadcrumb
-            :model="breadcrumbModel"
-            class="border-0 bg-transparent p-0 text-[13px]"
-          />
+          <AppBreadcrumb />
         </nav>
       </div>
     </template>
@@ -472,16 +412,10 @@ const userMenuItems = computed<MenuItem[]>(() => [
 
 <style scoped>
 /**
- * FIX 1: topbar-mark-shadow — inset directional box-shadow.
- * Tailwind has no inset-shadow utility at this depth/direction granularity → RFC §7.4.
- */
-.topbar-mark-shadow {
-  box-shadow: inset 0 -2px 0 rgb(0 0 0 / 10%);
-}
-
-/**
- * FIX 2: ws-mobile-btn-shadow — same inset shadow justification as above.
- * Background gradient is set via inline :style (dynamic hex pair from computeOrgGradient).
+ * ws-mobile-btn-shadow — inset directional box-shadow on the mobile workspace
+ * button. Tailwind has no inset-shadow utility at this depth/direction
+ * granularity → RFC §7.4 last-resort. Background gradient is set via inline
+ * :style (dynamic hex pair from computeOrgGradient).
  */
 .ws-mobile-btn-shadow {
   box-shadow: inset 0 -2px 0 rgb(0 0 0 / 10%);
diff --git a/apps/app/src/components-v2/layout/SidebarNav.vue b/apps/app/src/components-v2/layout/SidebarNav.vue
index 36365f3c..8fb82563 100644
--- a/apps/app/src/components-v2/layout/SidebarNav.vue
+++ b/apps/app/src/components-v2/layout/SidebarNav.vue
@@ -4,7 +4,7 @@
  *
  * Reads `APP_NAVIGATION` directly from `@/config/navigation`. This is the
  * single source of truth for sidebar items and breadcrumb derivation
- * (the breadcrumb side is served by `useNavBreadcrumb` over the same
+ * (the breadcrumb side is served by `useBreadcrumb` over the same
  * registry). Prior to P4, this component received a `groups` prop the
  * parent layout built from `@/navigation/vertical`; the prop chain
  * (OrganizerLayoutV2 → AppSidebar → SidebarNav) is removed.
diff --git a/apps/app/src/components-v2/layout/WorkspaceSwitcher.vue b/apps/app/src/components-v2/layout/WorkspaceSwitcher.vue
index ea4bdd57..012b0969 100644
--- a/apps/app/src/components-v2/layout/WorkspaceSwitcher.vue
+++ b/apps/app/src/components-v2/layout/WorkspaceSwitcher.vue
@@ -8,10 +8,24 @@
  * Popover: PrimeVue <Popover> replaces the manual document.mousedown
  * click-outside listener from crewli-starter. Toggle via popoverRef.toggle($event).
  *
+ * Plan 2.5 P5 Fix 5 (RFC §5.5): dropdown panel restructured per
+ * crewli-starter reference, with AD-2.5-W1 option A applied — dropdown
+ * rows render WITHOUT a sub line (organisation type / metrics deferred
+ * to a future RFC with backend scope — tracked as
+ * WORKSPACE-DROPDOWN-SUB-CONTENT). Known visual divergence: rows are
+ * ~16px shorter than crewli-starter; accepted.
+ *
+ * Semantic class names (.popover-head, .title, .link, .list, .opt,
+ * .is-current, .ws-logo, .name, .check-mark, .foot) are kept alongside
+ * the Tailwind utility classes as structural markers — they carry no
+ * scoped CSS rules (only the .ws-logo / .ws-logo-square-lg box-shadow
+ * exceptions below) and exist so specs can assert structure with
+ * stable selectors.
+ *
  * Icons: Crewli Icon.vue convention — name="tabler-x" :size="N".
  *
  * Styling: crewli-starter CSS selectors translated to Tailwind utilities inline.
- * One <style scoped> block covers the two exceptions documented below.
+ * One <style scoped> block covers the two box-shadow exceptions documented below.
  */
 
 import Popover from 'primevue/popover'
@@ -103,12 +117,25 @@ function selectOrg(ws: WorkspaceDisplay): void {
   authStore.setActiveOrganisation(ws.id)
   popoverRef.value?.hide()
 }
+
+// ---------------------------------------------------------------------------
+// Footer button placeholders — neither flow is wired in Plan 2.5 scope.
+// ---------------------------------------------------------------------------
+
+// TODO: wire to /v2/workspaces/new route or create-workspace dialog when ready
+function createWorkspace(): void {
+  console.warn('WorkspaceSwitcher: createWorkspace not yet implemented')
+}
+
+// TODO: wire to invite-user dialog when ready
+function inviteUser(): void {
+  console.warn('WorkspaceSwitcher: inviteUser not yet implemented')
+}
 </script>
 
 <template>
   <div class="relative flex-shrink-0 border-t border-[var(--p-content-border-color)] p-[10px]">
     <!-- Trigger button -->
-    <!-- .ws-switcher .trigger: flex, items-center, gap, w-full, px/py, rounded, border, bg-transparent, color, transition -->
     <button
       class="flex w-full items-center gap-[10px] rounded-[var(--p-border-radius)] border border-transparent bg-transparent px-[10px] py-[8px] text-[var(--p-text-color)] transition-colors duration-150 hover:bg-[var(--p-content-hover-background)]"
       :class="[
@@ -120,25 +147,22 @@ function selectOrg(ws: WorkspaceDisplay): void {
       <!-- Logo square (gradient background is bespoke: dynamic hex pair cannot be a static Tailwind class — RFC §7.4 justified inline-style) -->
       <span
         v-if="current"
-        class="ws-logo-square w-8 h-8 flex-shrink-0 rounded-[var(--p-border-radius)] inline-flex items-center justify-center text-white font-bold text-[12px]"
+        class="ws-logo ws-logo-square w-8 h-8 flex-shrink-0 rounded-[var(--p-border-radius)] inline-flex items-center justify-center text-white font-bold text-[12px]"
         :style="{ background: `linear-gradient(135deg, ${current.gradient[0]}, ${current.gradient[1]})` }"
       >
         {{ current.initials }}
       </span>
 
-      <!-- Meta: name (hidden in collapsed mode) -->
-      <!-- .ws-switcher .meta: flex-1, min-w-0, flex-col, line-height, text-left -->
+      <!-- Meta: name (hidden in collapsed mode). AD-2.5-W1 / P4: no sub. -->
       <span
         v-if="!collapsed && current"
         class="flex flex-1 min-w-0 flex-col text-left leading-[1.2]"
       >
-        <!-- .ws-switcher .meta .name: text-[13.5px], font-semibold, truncate -->
-        <span class="truncate text-[13.5px] font-semibold text-[var(--p-text-color)]">
+        <span class="name truncate text-[13.5px] font-semibold text-[var(--p-text-color)]">
           {{ current.name }}
         </span>
       </span>
 
-      <!-- Chevron (.ws-switcher .chev: color fg-subtle, flex-shrink-0) -->
       <Icon
         v-if="!collapsed"
         name="tabler-chevron-down"
@@ -149,47 +173,53 @@ function selectOrg(ws: WorkspaceDisplay): void {
 
     <!-- PrimeVue Popover — replaces crewli-starter's manual document.mousedown click-outside -->
     <Popover ref="popoverRef">
-      <!-- popover-head: px-[16px] py-[14px], border-bottom, flex, items-center, justify-between -->
-      <div class="flex items-center justify-between border-b border-[var(--p-content-border-color)] px-[16px] py-[14px]">
-        <!-- .popover-head .title -->
-        <span class="text-[15px] font-bold tracking-[-0.01em]">Workspaces</span>
-        <!-- .popover-head .link — TODO TECH-WS-GUI-REDESIGN: no manage-workspaces route yet -->
-        <span class="cursor-pointer text-[13px] font-medium text-[var(--p-primary-color)]">Manage</span>
+      <!-- Header -->
+      <div class="popover-head flex items-center justify-between border-b border-[var(--p-content-border-color)] px-[16px] py-[14px]">
+        <span class="title text-[15px] font-bold tracking-[-0.01em]">Workspaces</span>
+        <!--
+          TODO TECH-WS-GUI-REDESIGN: no v2-workspaces-manage route yet —
+          rendered as a non-navigating label per the routeName-undefined
+          convention (registry-style). Becomes a RouterLink when the
+          manage-workspaces page lands.
+        -->
+        <span class="link cursor-pointer text-[13px] font-medium text-[var(--p-primary-color)]">Manage</span>
       </div>
 
-      <!-- .pop-ws .list: p-[6px] -->
-      <div class="min-w-[280px] p-[6px]">
-        <!-- .pop-ws .opt: grid 3-col, gap, p, rounded, cursor-pointer -->
+      <!-- List of organisations -->
+      <div class="list min-w-[280px] p-[6px]">
         <!-- TODO TECH-WS-GUI-REDESIGN: full listbox/menu ARIA (role, roving tabindex, arrow-key nav) — tracked -->
         <button
           v-for="ws in allOrgs"
           :key="ws.id"
           type="button"
-          class="grid w-full grid-cols-[36px_1fr_auto] cursor-pointer items-center gap-[12px] rounded-[var(--p-border-radius)] border-0 bg-transparent p-[10px] text-start hover:bg-[var(--p-content-hover-background)]"
+          class="opt grid w-full grid-cols-[36px_1fr_auto] cursor-pointer items-center gap-[12px] rounded-[var(--p-border-radius)] border-0 bg-transparent p-[10px] text-start hover:bg-[var(--p-content-hover-background)]"
           :class="[
-            ws.id === current?.id ? 'bg-[var(--p-primary-50)]' : '',
+            ws.id === current?.id ? 'is-current bg-[var(--p-primary-50)]' : '',
           ]"
           :aria-current="current?.id === ws.id ? 'true' : undefined"
           @click="selectOrg(ws)"
         >
-          <!-- Org logo — larger variant (36px) with dynamic gradient (same inline-style justification as trigger) -->
+          <!-- Org logo (large variant) — dynamic gradient via inline :style -->
           <span
-            class="ws-logo-square-lg w-9 h-9 flex-shrink-0 rounded-[var(--p-border-radius)] inline-flex items-center justify-center text-white font-bold text-[13px]"
+            class="ws-logo lg ws-logo-square-lg w-9 h-9 flex-shrink-0 rounded-[var(--p-border-radius)] inline-flex items-center justify-center text-white font-bold text-[13px]"
             :style="{ background: `linear-gradient(135deg, ${ws.gradient[0]}, ${ws.gradient[1]})` }"
           >{{ ws.initials }}</span>
 
-          <!-- Name -->
+          <!--
+            Name only. AD-2.5-W1 option A: no .sub line on dropdown items
+            until WORKSPACE-DROPDOWN-SUB-CONTENT RFC lands with backend
+            (organisations.type enum + metrics endpoint).
+          -->
           <span>
-            <!-- .pop-ws .opt .name -->
-            <div class="text-[14px] font-semibold text-[var(--p-text-color)]">{{ ws.name }}</div>
+            <div class="name text-[14px] font-semibold text-[var(--p-text-color)]">{{ ws.name }}</div>
           </span>
 
-          <!-- Check mark for active org (.pop-ws .opt .check-mark) -->
+          <!-- Check mark for active org -->
           <Icon
             v-if="ws.id === current?.id"
             name="tabler-check"
             :size="18"
-            class="text-[var(--p-primary-color)]"
+            class="check-mark text-[var(--p-primary-color)]"
           />
           <!-- Spacer when not current (keeps grid alignment) -->
           <span
@@ -199,18 +229,24 @@ function selectOrg(ws: WorkspaceDisplay): void {
         </button>
       </div>
 
-      <!-- Footer (.pop-ws .foot: p-[8px], border-top, flex, gap-[4px]) -->
-      <div class="flex gap-[4px] border-t border-[var(--p-content-border-color)] p-[8px]">
-        <!-- TODO TECH-WS-GUI-REDESIGN: create-workspace route not yet defined -->
-        <button class="inline-flex flex-1 h-[36px] items-center justify-center gap-[6px] rounded-[var(--p-border-radius)] border-0 bg-transparent text-[13px] font-medium text-[var(--p-text-color)] hover:bg-[var(--p-content-hover-background)]">
+      <!-- Footer -->
+      <div class="foot flex gap-[4px] border-t border-[var(--p-content-border-color)] p-[8px]">
+        <button
+          type="button"
+          class="inline-flex flex-1 h-[36px] items-center justify-center gap-[6px] rounded-[var(--p-border-radius)] border-0 bg-transparent text-[13px] font-medium text-[var(--p-text-color)] hover:bg-[var(--p-content-hover-background)]"
+          @click="createWorkspace"
+        >
           <Icon
             name="tabler-plus"
             :size="14"
           />
           New workspace
         </button>
-        <!-- TODO TECH-WS-GUI-REDESIGN: invite route not yet defined -->
-        <button class="inline-flex flex-1 h-[36px] items-center justify-center gap-[6px] rounded-[var(--p-border-radius)] border-0 bg-transparent text-[13px] font-medium text-[var(--p-text-color)] hover:bg-[var(--p-content-hover-background)]">
+        <button
+          type="button"
+          class="inline-flex flex-1 h-[36px] items-center justify-center gap-[6px] rounded-[var(--p-border-radius)] border-0 bg-transparent text-[13px] font-medium text-[var(--p-text-color)] hover:bg-[var(--p-content-hover-background)]"
+          @click="inviteUser"
+        >
           <Icon
             name="tabler-user-plus"
             :size="14"
@@ -224,7 +260,7 @@ function selectOrg(ws: WorkspaceDisplay): void {
 
 <style scoped>
 /**
- * FIX 2: ws-logo-square — width/height moved to Tailwind (w-8 h-8 on the element).
+ * ws-logo-square — width/height moved to Tailwind (w-8 h-8 on the element).
  * Tailwind has no inset directional box-shadow utility at this granularity →
  * scoped CSS last resort per RFC §7.4.
  */
@@ -233,7 +269,7 @@ function selectOrg(ws: WorkspaceDisplay): void {
 }
 
 /**
- * FIX 2: ws-logo-square-lg — width/height moved to Tailwind (w-9 h-9 on the element).
+ * ws-logo-square-lg — width/height moved to Tailwind (w-9 h-9 on the element).
  * Same box-shadow exception as above (inset shadow has no Tailwind equivalent).
  * Background gradient set via inline :style on the element (dynamic hex pair).
  */
diff --git a/apps/app/src/components-v2/layout/__tests__/AppTopbar.spec.ts b/apps/app/src/components-v2/layout/__tests__/AppTopbar.spec.ts
index aefb87ee..bef4a510 100644
--- a/apps/app/src/components-v2/layout/__tests__/AppTopbar.spec.ts
+++ b/apps/app/src/components-v2/layout/__tests__/AppTopbar.spec.ts
@@ -9,14 +9,11 @@
  *  2. Theme toggle click → shell.setTheme with flipped value (light→dark, dark→light)
  *  3. Density toggle click → shell.setDensity with flipped value
  *  4. User-menu Sign out command → authStore.logout called
- *  5. Breadcrumb model mapping:
- *     - non-last items carry a `command` that calls router.push with the item's `to`
- *     - last item has NO `command` (non-interactive) and NO `route` key (FIX A regression)
+ *  5. AppBreadcrumb is rendered in the #start slot (Plan 2.5 P5 Fix 2).
  *
- * useBreadcrumb() calls useRoute() internally. We provide a minimal
- * vue-router mock via vi.mock so the composable has a route to call.
- * useRoute is exposed as a vi.fn() so individual tests can override the
- * matched records without re-importing the module.
+ * AppBreadcrumb (and its useBreadcrumb composable) is stubbed so this spec
+ * never reaches the real route-driven walkNavTree path — breadcrumb-derivation
+ * coverage lives in useBreadcrumb.spec.ts.
  */
 
 import { createPinia, setActivePinia } from 'pinia'
@@ -27,23 +24,15 @@ import { useAuthStore } from '@/stores/useAuthStore'
 import AppTopbar from '@/components-v2/layout/AppTopbar.vue'
 
 // ---------------------------------------------------------------------------
-// Mock vue-router (useBreadcrumb calls useRoute internally).
-// vi.hoisted() initialises these vi.fn() instances before the vi.mock()
-// factory runs. Vitest hoists vi.hoisted() + vi.mock() above all imports,
-// so the mock is registered before AppTopbar's transitive vue-router
-// import resolves — physical import order here is irrelevant to that.
+// Mock vue-router — AppTopbar no longer uses useRoute/useRouter directly, but
+// PrimeVue's stubbed components and AppBreadcrumb (stubbed below) may import
+// from vue-router transitively. A minimal mock keeps the test environment lean.
 // ---------------------------------------------------------------------------
 
-const { mockRouterPush, mockUseRoute } = vi.hoisted(() => ({
-  mockRouterPush: vi.fn(),
-  mockUseRoute: vi.fn(() => ({ matched: [] as unknown[] })),
-}))
-
 vi.mock('vue-router', () => ({
-  useRoute: mockUseRoute,
-  useRouter: () => ({
-    push: mockRouterPush,
-  }),
+  useRoute: () => ({ name: 'v2-dashboard' }),
+  useRouter: () => ({ push: vi.fn() }),
+  RouterLink: { name: 'RouterLink', props: ['to'], template: '<a><slot /></a>' },
 }))
 
 // ---------------------------------------------------------------------------
@@ -63,7 +52,7 @@ const MenubarStub = {
 
 const globalStubs = {
   Menubar: MenubarStub,
-  Breadcrumb: { name: 'Breadcrumb', props: ['model'], template: '<nav class="breadcrumb-stub" />' },
+  AppBreadcrumb: { name: 'AppBreadcrumb', template: '<nav class="app-breadcrumb-stub" data-testid="app-breadcrumb-stub" />' },
   InputText: { name: 'InputText', template: '<input class="input-text-stub" />' },
   OverlayBadge: { name: 'OverlayBadge', props: ['value', 'severity'], template: '<div class="overlay-badge-stub"><slot /></div>' },
   Popover: {
@@ -106,11 +95,6 @@ function mountTopbar() {
 describe('AppTopbar', () => {
   beforeEach(() => {
     setActivePinia(createPinia())
-    mockRouterPush.mockReset()
-    mockUseRoute.mockReset()
-
-    // Default: empty matched array (no breadcrumb items)
-    mockUseRoute.mockReturnValue({ matched: [] })
   })
 
   // -------------------------------------------------------------------------
@@ -248,55 +232,16 @@ describe('AppTopbar', () => {
   })
 
   // -------------------------------------------------------------------------
-  // FIX A regression: breadcrumb model mapping uses command+router.push,
-  // NOT the `route` key that this PrimeVue Breadcrumb version ignores.
-  //
-  // BreadcrumbItem.vue renders <a :href="item.url || '#'"> and calls
-  // item.command on click — it never reads `route`. This test would have
-  // caught the broken mapping that set `route` instead of `command`.
+  // Plan 2.5 P5 Fix 2: AppTopbar #start renders <AppBreadcrumb /> (not the
+  // legacy PrimeVue Breadcrumb fed by a route-meta mapping). Breadcrumb
+  // derivation coverage lives in useBreadcrumb.spec.ts.
   // -------------------------------------------------------------------------
 
-  it('breadcrumb model: non-last items have command that calls router.push; last item has no command and no route key', async () => {
-    // Provide two matched records so we get a non-last item (with `to`) and
-    // a last item (current, no `to`).
-    mockUseRoute.mockReturnValue({
-      matched: [
-        { meta: { breadcrumb: 'Dashboard' }, name: 'dashboard', path: '/dashboard' },
-        { meta: { breadcrumb: 'Events' }, name: 'events', path: '/events' },
-      ],
-    })
-
+  it('renders <AppBreadcrumb /> inside the Menubar #start slot', () => {
     const wrapper = mountTopbar()
+    const bar = wrapper.findComponent(MenubarStub)
 
-    const breadcrumbStub = wrapper.findComponent({ name: 'Breadcrumb' })
-
-    expect(breadcrumbStub.exists()).toBe(true)
-
-    const model = breadcrumbStub.props('model') as Array<{
-      label: string
-      command?: () => void
-      route?: unknown
-    }>
-
-    // Should have two items produced by toBreadcrumbItems
-    expect(model).toHaveLength(2)
-
-    const [firstItem, lastItem] = model as [typeof model[0], typeof model[0]]
-
-    // Non-last item: must carry `command`, must NOT carry `route`
-    expect(firstItem.label).toBe('Dashboard')
-    expect(typeof firstItem.command).toBe('function')
-    expect('route' in firstItem).toBe(false)
-
-    // Invoking command must call router.push with the item's resolved `to` path
-    firstItem.command!()
-    expect(mockRouterPush).toHaveBeenCalledOnce()
-    expect(mockRouterPush).toHaveBeenCalledWith('/dashboard')
-
-    // Last/current item: must have NO command (non-interactive), NO `route` key
-    expect(lastItem.label).toBe('Events')
-    expect(lastItem.command).toBeUndefined()
-    expect('route' in lastItem).toBe(false)
+    expect(bar.find('[data-testid="app-breadcrumb-stub"]').exists()).toBe(true)
   })
 
   // -------------------------------------------------------------------------
diff --git a/apps/app/src/components-v2/layout/__tests__/WorkspaceSwitcher.spec.ts b/apps/app/src/components-v2/layout/__tests__/WorkspaceSwitcher.spec.ts
index 83e099d6..e71f0d07 100644
--- a/apps/app/src/components-v2/layout/__tests__/WorkspaceSwitcher.spec.ts
+++ b/apps/app/src/components-v2/layout/__tests__/WorkspaceSwitcher.spec.ts
@@ -1,11 +1,16 @@
 /**
- * WorkspaceSwitcher.spec.ts — regression coverage for AD-2.5-W1.
+ * WorkspaceSwitcher.spec.ts
  *
- * Scope: assert that the workspace switcher no longer renders a "sub" line
- * (previously the role string sourced from org.role). The full popover /
- * org-switch behaviour is left to Storybook visual coverage; this file
- * exists solely as the AD-2.5-W1 lock against re-introduction of the sub
- * meta line in the trigger or in the popover row.
+ * Locks two slices of contract:
+ *   1. AD-2.5-W1 + AD-2.5-W1 option A: NO sub line on trigger OR on any
+ *      dropdown row.
+ *   2. Plan 2.5 P5 Fix 5: dropdown panel structure per crewli-starter —
+ *      header (title + manage link), list (one .opt per org, .is-current
+ *      + .check-mark on active), footer (two buttons).
+ *
+ * Popover is stubbed as a simple slot passthrough so its content renders
+ * inline and `wrapper.find('.popover-head')` etc. resolve without
+ * teleporting to <body>.
  */
 
 import { createPinia, setActivePinia } from 'pinia'
@@ -28,12 +33,9 @@ const userFixture: User = {
   avatar: null,
 }
 
-const orgFixture: Organisation = {
-  id: 'org_a',
-  name: 'Festival Crew NL',
-  slug: 'festival-crew-nl',
-  role: 'org_admin',
-}
+const orgA: Organisation = { id: 'org_a', name: 'Festival Crew NL', slug: 'festival-crew-nl', role: 'org_admin' }
+const orgB: Organisation = { id: 'org_b', name: 'Stadspark Events', slug: 'stadspark-events', role: 'org_member' }
+const orgC: Organisation = { id: 'org_c', name: 'Volunteer Collective', slug: 'volunteer-collective', role: 'event_manager' }
 
 const globalStubs = {
   Icon: { template: '<span class="icon-stub" />' },
@@ -47,13 +49,13 @@ const globalStubs = {
   },
 }
 
-function mountSwitcher() {
+function mountSwitcher(opts: { orgs?: Organisation[] } = {}) {
   setActivePinia(createPinia())
 
   const auth = useAuthStore()
 
   auth.user = userFixture
-  auth.organisations = [orgFixture]
+  auth.organisations = opts.orgs ?? [orgA, orgB, orgC]
 
   return mount(WorkspaceSwitcher, {
     props: { collapsed: false },
@@ -68,19 +70,87 @@ describe('WorkspaceSwitcher', () => {
     setActivePinia(createPinia())
   })
 
-  it('does not render a sub line (AD-2.5-W1)', () => {
-    const wrapper = mountSwitcher()
+  // -------------------------------------------------------------------------
+  // AD-2.5-W1 — no sub on trigger
+  // -------------------------------------------------------------------------
 
-    // Role string used to back the sub line — must not leak into rendered output.
-    expect(wrapper.text()).not.toContain(orgFixture.role)
+  it('does not render a sub line on the trigger (AD-2.5-W1)', () => {
+    const wrapper = mountSwitcher({ orgs: [orgA] })
 
-    // No selector / class tied to the removed sub element.
+    expect(wrapper.text()).not.toContain(orgA.role)
     expect(wrapper.html()).not.toMatch(/workspace-sub|ws-sub|meta-sub/)
   })
 
-  it('renders the workspace name', () => {
-    const wrapper = mountSwitcher()
+  it('renders the workspace name on the trigger', () => {
+    const wrapper = mountSwitcher({ orgs: [orgA] })
 
-    expect(wrapper.text()).toContain(orgFixture.name)
+    expect(wrapper.text()).toContain(orgA.name)
+  })
+
+  // -------------------------------------------------------------------------
+  // Fix 5 — dropdown panel structure
+  // -------------------------------------------------------------------------
+
+  describe('dropdown panel (Fix 5)', () => {
+    it('renders header with Workspaces title and Manage link', () => {
+      const wrapper = mountSwitcher()
+
+      const head = wrapper.find('.popover-head')
+
+      expect(head.exists()).toBe(true)
+      expect(head.find('.title').text()).toBe('Workspaces')
+      expect(head.find('.link').exists()).toBe(true)
+      expect(head.find('.link').text()).toBe('Manage')
+    })
+
+    it('renders one .opt row per organisation', () => {
+      const wrapper = mountSwitcher()
+
+      expect(wrapper.findAll('.opt')).toHaveLength(3)
+    })
+
+    it('renders check-mark and is-current only on the current organisation', () => {
+      const wrapper = mountSwitcher()
+
+      // currentOrganisation defaults to organisations[0] (= orgA) when no
+      // active id is set; the switcher's allOrgs sort puts the current org
+      // first, so .opt[0] is the current row.
+      const opts = wrapper.findAll('.opt')
+
+      expect(opts[0].classes()).toContain('is-current')
+      expect(opts[0].find('.check-mark').exists()).toBe(true)
+
+      expect(opts[1].classes()).not.toContain('is-current')
+      expect(opts[1].find('.check-mark').exists()).toBe(false)
+    })
+
+    it('renders footer with New workspace and Invite buttons', () => {
+      const wrapper = mountSwitcher()
+
+      const foot = wrapper.find('.foot')
+
+      expect(foot.exists()).toBe(true)
+
+      const buttons = foot.findAll('button')
+
+      expect(buttons).toHaveLength(2)
+      expect(buttons[0].text()).toContain('New workspace')
+      expect(buttons[1].text()).toContain('Invite')
+    })
+
+    it('does not render sub lines on any dropdown row (AD-2.5-W1 option A)', () => {
+      const wrapper = mountSwitcher()
+
+      // No .opt row carries a .sub descendant; no role string leaks into
+      // the dropdown text (org_admin, org_member, event_manager are the
+      // backing roles for the 3-org fixture).
+      expect(wrapper.find('.opt .sub').exists()).toBe(false)
+
+      const listText = wrapper.find('.list').text()
+
+      expect(listText).not.toContain('org_admin')
+      expect(listText).not.toContain('org_member')
+      expect(listText).not.toContain('event_manager')
+    })
   })
 })
diff --git a/apps/app/src/composables/__tests__/useBreadcrumb.spec.ts b/apps/app/src/composables/__tests__/useBreadcrumb.spec.ts
index f54c7247..9775efdd 100644
--- a/apps/app/src/composables/__tests__/useBreadcrumb.spec.ts
+++ b/apps/app/src/composables/__tests__/useBreadcrumb.spec.ts
@@ -1,158 +1,9 @@
 import { describe, expect, it } from 'vitest'
-import { toBreadcrumbItems, walkNavTree } from '@/composables/useBreadcrumb'
-import type { BreadcrumbRouteRecord } from '@/composables/useBreadcrumb'
+import { walkNavTree } from '@/composables/useBreadcrumb'
 import type { NavItem } from '@/config/navigation'
 
 // ---------------------------------------------------------------------------
-// Fixtures
-// ---------------------------------------------------------------------------
-
-const withTitle = (title: string, path: string): BreadcrumbRouteRecord => ({
-  meta: { title },
-  path,
-})
-
-const withBreadcrumb = (breadcrumb: string, path: string): BreadcrumbRouteRecord => ({
-  meta: { breadcrumb },
-  path,
-})
-
-const withBoth = (title: string, breadcrumb: string, path: string): BreadcrumbRouteRecord => ({
-  meta: { title, breadcrumb },
-  path,
-})
-
-const withNeither = (path: string): BreadcrumbRouteRecord => ({
-  meta: {},
-  path,
-})
-
-const withNoMeta = (path: string): BreadcrumbRouteRecord => ({
-  path,
-})
-
-// ---------------------------------------------------------------------------
-// Tests
-// ---------------------------------------------------------------------------
-
-describe('toBreadcrumbItems', () => {
-  it('returns empty array for empty matched', () => {
-    expect(toBreadcrumbItems([])).toEqual([])
-  })
-
-  it('filters out records that have neither meta.title nor meta.breadcrumb', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withNeither('/'),
-      withNoMeta('/events'),
-      withTitle('Events', '/events'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items).toHaveLength(1)
-    expect(items[0].label).toBe('Events')
-  })
-
-  it('uses meta.breadcrumb as label when set', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withBreadcrumb('Home base', '/'),
-      withBreadcrumb('Events overview', '/events'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items[0].label).toBe('Home base')
-    expect(items[1].label).toBe('Events overview')
-  })
-
-  it('uses meta.title as label when meta.breadcrumb is absent', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withTitle('Dashboard', '/dashboard'),
-      withTitle('Settings', '/settings'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items[0].label).toBe('Dashboard')
-    expect(items[1].label).toBe('Settings')
-  })
-
-  it('prefers meta.breadcrumb over meta.title when both are present', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withBoth('Long Title', 'Short', '/events'),
-      withTitle('Current', '/events/detail'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items[0].label).toBe('Short')
-  })
-
-  it('last item has no `to` (current page)', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withTitle('Events', '/events'),
-      withTitle('Detail', '/events/detail'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items).toHaveLength(2)
-    expect(items[1].to).toBeUndefined()
-  })
-
-  it('non-last items carry a `to` link', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withTitle('Home', '/'),
-      withTitle('Events', '/events'),
-      withTitle('Detail', '/events/detail'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items[0].to).toBe('/')
-    expect(items[1].to).toBe('/events')
-    expect(items[2].to).toBeUndefined()
-  })
-
-  it('single eligible record: label set, no `to`', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      withTitle('Dashboard', '/dashboard'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items).toHaveLength(1)
-    expect(items[0].label).toBe('Dashboard')
-    expect(items[0].to).toBeUndefined()
-  })
-
-  it('falls back to name-based RouteLocationRaw when path is absent', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      { meta: { title: 'Home' }, name: 'home' },
-      { meta: { title: 'Current' }, name: 'current' },
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items[0].to).toEqual({ name: 'home' })
-    expect(items[1].to).toBeUndefined()
-  })
-
-  it('records with no meta at all are filtered out', () => {
-    const matched: BreadcrumbRouteRecord[] = [
-      { path: '/layout' },
-      withTitle('Dashboard', '/dashboard'),
-    ]
-
-    const items = toBreadcrumbItems(matched)
-
-    expect(items).toHaveLength(1)
-    expect(items[0].label).toBe('Dashboard')
-  })
-})
-
-// ---------------------------------------------------------------------------
-// AD-2.5-B1 — walkNavTree (registry-driven breadcrumb)
+// walkNavTree — registry-driven breadcrumb chain extraction.
 // Local FIXTURE keeps these specs independent of APP_NAVIGATION content.
 // ---------------------------------------------------------------------------
 
@@ -174,7 +25,7 @@ const FIXTURE: NavItem[] = [
   },
 ]
 
-describe('walkNavTree (AD-2.5-B1)', () => {
+describe('walkNavTree', () => {
   it('returns single-entry chain for a top-level leaf', () => {
     expect(walkNavTree(FIXTURE, 'a')).toEqual([
       { label: 'A', routeName: 'a' },
diff --git a/apps/app/src/composables/useBreadcrumb.ts b/apps/app/src/composables/useBreadcrumb.ts
index fc421758..8dd0e4cd 100644
--- a/apps/app/src/composables/useBreadcrumb.ts
+++ b/apps/app/src/composables/useBreadcrumb.ts
@@ -1,115 +1,13 @@
 import { computed } from 'vue'
 import { useRoute } from 'vue-router'
 import type { ComputedRef } from 'vue'
-import type { RouteLocationRaw } from 'vue-router'
 import { APP_NAVIGATION, type NavItem } from '@/config/navigation'
 
-// ---------------------------------------------------------------------------
-// Types — legacy (meta-based, consumed by AppTopbar pre-P4)
-// ---------------------------------------------------------------------------
-
-/** A single breadcrumb item. `to` is absent for the current (last) item. */
+/**
+ * Breadcrumb item derived from APP_NAVIGATION. The `routeName` is mapped
+ * at render time to `{ name: routeName }` for RouterLink (see AppBreadcrumb).
+ */
 export interface BreadcrumbItem {
-  label: string
-  to?: RouteLocationRaw
-}
-
-/**
- * Minimal shape we need from a matched route record.
- * Using a structural type keeps the pure helper testable without
- * requiring full RouteLocationMatched fixtures in unit tests.
- * RouteLocationMatched is structurally assignable to this interface so
- * route.matched (RouteLocationMatched[]) passes the type-checker.
- */
-export interface BreadcrumbRouteRecord {
-  meta?: Record<string, unknown> & {
-    breadcrumb?: string
-    title?: string
-  }
-  name?: string | symbol | null
-  path?: string
-}
-
-// ---------------------------------------------------------------------------
-// Pure helper — testable without a live router
-// ---------------------------------------------------------------------------
-
-/**
- * Convert an array of matched route records into breadcrumb items.
- *
- * Rules:
- * - Records without `meta.breadcrumb` OR `meta.title` are filtered out.
- * - Label = `meta.breadcrumb` if set, else `meta.title`.
- * - The last item is current — no `to` link.
- * - All preceding items carry a `to` pointing at their `path` (or `name`
- *   when path is absent).
- */
-export function toBreadcrumbItems(matched: readonly BreadcrumbRouteRecord[]): BreadcrumbItem[] {
-  const eligible = matched.filter(
-    r => r.meta?.breadcrumb !== undefined || r.meta?.title !== undefined,
-  )
-
-  return eligible.map((record, index): BreadcrumbItem => {
-    const label = (record.meta?.breadcrumb ?? record.meta?.title) as string
-    const isLast = index === eligible.length - 1
-
-    if (isLast)
-      return { label }
-
-    // Prefer path; fall back to name when path is absent/empty.
-    // NOTE: a non-last record whose `path` is a param template (e.g. `/events/:id`)
-    // would yield an unresolved-template `to` — acceptable in foundation scope because
-    // param routes are normally the last (current, no-`to`) segment.
-    // TODO TECH-WS-GUI-REDESIGN: resolve param paths if a non-leaf param route ever needs a crumb link
-    const to: RouteLocationRaw
-      = record.path
-        ? record.path
-        : { name: record.name as string }
-
-    return { label, to }
-  })
-}
-
-// ---------------------------------------------------------------------------
-// Composable — thin wrapper around useRoute()
-// ---------------------------------------------------------------------------
-
-export interface UseBreadcrumbReturn {
-  items: ComputedRef<BreadcrumbItem[]>
-}
-
-/**
- * Composable that derives breadcrumb items from the current route's
- * `matched` array. Reactive — updates automatically on navigation.
- *
- * NOTE (AD-2.5-B1): this `route.matched` + `meta` derivation is the
- * pre-Plan-2.5 mechanism, still consumed by AppTopbar. P4 (RFC §8
- * step 4) migrates AppTopbar to `useNavBreadcrumb` below; after that,
- * this legacy function and its types should be retired and
- * `useNavBreadcrumb` renamed to `useBreadcrumb` as the single SoT.
- */
-export function useBreadcrumb(): UseBreadcrumbReturn {
-  const route = useRoute()
-
-  const items = computed<BreadcrumbItem[]>(() =>
-    toBreadcrumbItems(route.matched),
-  )
-
-  return { items }
-}
-
-// ---------------------------------------------------------------------------
-// AD-2.5-B1 — registry-driven breadcrumb (Plan 2.5 P1 foundation)
-// ---------------------------------------------------------------------------
-
-/**
- * Breadcrumb item derived from APP_NAVIGATION. Distinct from the legacy
- * `BreadcrumbItem` above which carries a `RouteLocationRaw to` field;
- * this shape carries a route NAME, mapped at render time to
- * `{ name: routeName }`. Both shapes reconcile in P4 when AppTopbar
- * migrates and the legacy API is removed.
- */
-export interface NavBreadcrumbItem {
   label: string
   routeName?: string
 }
@@ -118,13 +16,13 @@ export interface NavBreadcrumbItem {
  * Walks a NavItem tree to find the chain from root to the leaf whose
  * `routeName` matches the given name. Returns an empty array if no match.
  *
- * AD-2.5-B1: pure function — unit-testable without router or component mount.
+ * Pure function — unit-testable without router or component mount.
  */
 export function walkNavTree(
   tree: NavItem[],
   routeName: string,
-  acc: NavBreadcrumbItem[] = [],
-): NavBreadcrumbItem[] {
+  acc: BreadcrumbItem[] = [],
+): BreadcrumbItem[] {
   for (const node of tree) {
     const next = [...acc, { label: node.label, routeName: node.routeName }]
 
@@ -146,14 +44,14 @@ export function walkNavTree(
  * Returns the breadcrumb chain for the current route, derived from
  * APP_NAVIGATION. Empty array when `route.name` is unset or no match.
  *
- * AD-2.5-B1. Transitional name: in P4 (RFC §8 step 4), AppTopbar
- * migrates from the legacy `useBreadcrumb` above to this composable;
- * after that, rename this to `useBreadcrumb` and drop the legacy API.
+ * The breadcrumb's single source of truth is APP_NAVIGATION (shared with
+ * SidebarNav); the prior route-meta-driven mechanism was retired in
+ * Plan 2.5 P5.
  */
-export function useNavBreadcrumb(): ComputedRef<NavBreadcrumbItem[]> {
+export function useBreadcrumb(): ComputedRef<BreadcrumbItem[]> {
   const route = useRoute()
 
-  return computed<NavBreadcrumbItem[]>(() => {
+  return computed<BreadcrumbItem[]>(() => {
     if (!route.name)
       return []