feat(layout): Plan 2.5 P5 — shell parity fixes 1–5 + useBreadcrumb retire

Per RFC-WS-PRIMEVUE-PLAN-2-5 §5.1–§5.5 plus the AD-2.5-W1 option-A
supersession (no sub on dropdown items either, accepted divergence).

Atomic changes:
- AppTopbar: brand block (gradient "C" mark + Crewli wordmark) removed
  per Fix 1; the #start slot now renders <AppBreadcrumb /> per Fix 2.
  Legacy meta-based useBreadcrumb consumption (breadcrumbModel computed,
  vue-router useRouter import, command-based PrimeVue Breadcrumb model)
  is gone; AppBreadcrumb owns the registry-driven path. Dead
  topbar-mark-shadow scoped CSS rule deleted.
- AppBreadcrumb: import updated to the renamed useBreadcrumb.
- AppSidebar: docstring updated to make the Fix 3 vertical order
  (Header → Nav → Switcher, switcher bottom-anchored) explicit. No
  template change needed: SidebarNav's root <nav class="flex-1"> already
  fills available column space, naturally pushing WorkspaceSwitcher to
  the bottom (two flex-1 siblings would split the column 50/50 and
  compress the nav — a separate spacer element is structurally wrong).
- WorkspaceSwitcher: dropdown panel restructured per crewli-starter
  reference. Semantic class markers (.popover-head/.title/.link/.list/
  .opt/.is-current/.ws-logo/.name/.check-mark/.foot) added alongside
  Tailwind utilities so specs assert structure with stable selectors.
  Footer buttons wired to placeholder createWorkspace / inviteUser
  handlers (console.warn + TODO) until the flows ship. Manage link
  stays a non-navigating label (no v2-workspaces-manage route yet).
  No sub line on any dropdown row (AD-2.5-W1 option A).

Atomic legacy useBreadcrumb retirement (planned since P1):
- Legacy route-meta-driven useBreadcrumb + toBreadcrumbItems +
  BreadcrumbRouteRecord types deleted entirely (only AppTopbar
  consumed it, and that consumption is gone after Fix 2).
- useNavBreadcrumb → useBreadcrumb (single SoT for breadcrumb chain).
- NavBreadcrumbItem → BreadcrumbItem.
- AppBreadcrumb.vue import updated to the new name.
- SidebarNav.vue docstring reference scrubbed to the new name.
- useBreadcrumb.spec.ts: 10 legacy toBreadcrumbItems specs removed;
  4 walkNavTree specs retained.

AppTopbar.spec.ts:
- vue-router mock simplified (route.matched no longer relevant).
- AppBreadcrumb stubbed in #start; legacy command-vs-route assertion
  removed; new spec verifies AppBreadcrumb is rendered.

WorkspaceSwitcher.spec.ts: 5 new dropdown specs (header / row count /
current-row checkmark / footer buttons / no-sub on rows).

Suite delta: 557 → 552 (−5 net: −10 legacy toBreadcrumbItems specs,
+5 Fix 5 dropdown specs, −1 obsolete AppTopbar breadcrumb-model spec,
+1 new AppTopbar AppBreadcrumb-presence spec).

vue-tsc clean. Scoped ESLint clean (0 errors). All 3 re-grep checks
returned 0 hits (useNavBreadcrumb/NavBreadcrumbItem, topbar brand
selectors, standalone "sub" identifier in WorkspaceSwitcher — only
documentation comments referencing the no-sub state remain, which
describe absence by design).

Manual smoke skipped (Auto Mode); coverage from the post-edit specs
includes AppBreadcrumb-in-#start, dropdown structure, and trigger
no-sub. Recommend Bert run `pnpm --filter crewli-app dev` and verify
the 6 checks listed in the prompt before merging.

Known divergence from crewli-starter (accepted):
- Dropdown rows are ~16px shorter than crewli-starter (no sub line).
  Tracked as WORKSPACE-DROPDOWN-SUB-CONTENT for a future RFC with
  the required backend scope (organisations.type enum + metrics).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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']>