style(layout): sidebar brand-square symmetry + WorkspaceSwitcher trigger polish

Plan 2.5 P6 follow-up. Closes two desktop shell-parity gaps from P6
manual smoke against crewli-starter SoT:

- Sidebar logo decoupled from the collapse toggle. Expanded layout is
  now justify-between (brand group left, collapse chevron right) and
  collapsed layout is justify-center with the logo alone. The expand
  affordance becomes a small absolute-positioned circular button at
  the rail's right edge — solid background + border so the slight
  overlap with the centred logo reads as a tucked-in chip rather than
  a collision. Toggling collapsed no longer shifts the logo.
- Brand square (SidebarHeader logo) and workspace avatar
  (WorkspaceSwitcher trigger) unified to the same rounded square
  (h-8 w-8 rounded-xl). Existing sizes were already consistent at
  32px — radius bumped from rounded-lg (8px) / var(--p-border-radius)
  (~6px) to rounded-xl (12px) per the design direction. Collapsed
  rail now reads as a vertical mirror: brand square at the top,
  avatar square at the bottom, bracketing the nav icons.
- WorkspaceSwitcher trigger restyled: rounded-xl (was the sharper
  var-radius), p-2 (was px-[10px] py-[8px]), hover background. The
  collapsed-variant gating of name + chevron is unchanged from P5.

Edge-mounted overhang past the rail edge was not possible: the aside
carries `overflow-hidden` (intentional, for the w-64 ⇄ w-16 width
transition) which clips anything past the rail edge. The tucked-chip
pattern (24px circle at end-0, solid bg) is the visual compromise —
the affordance stays inside the rail, discoverable, and visually
decoupled from the logo.

Desktop only. Mobile drawer chrome (logo placement, drawer X button,
missing switcher) tracked separately as MOBILE-SHELL-PARITY.

Tests:
- +2 WorkspaceSwitcher.spec.ts: trigger uses rounded-xl; collapsed
  trigger renders avatar only (hides .meta).
- +1 SidebarHeader.spec.ts: collapsed row hides the .brand-name
  wordmark and toggles to justify-center (logo-stays-centred lock).

Suite delta: 558 → 561 (+3). vue-tsc clean. Scoped ESLint clean
(0 errors, pre-existing warnings only).

Manual smoke pending Bert: collapse the rail, verify logo stays put
and the expand chip appears at the right edge; verify the trigger
shows rounded corners + hover bg; verify the collapsed avatar
mirrors the brand square size/radius.

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

apps/app/src/components-v2/layout/WorkspaceSwitcher.vue

@@ -135,19 +135,27 @@ function inviteUser(): void {
 
 <template>
   <div class="relative flex-shrink-0 border-t border-[var(--p-content-border-color)] p-[10px]">
-    <!-- Trigger button -->
+    <!--
+      Trigger button.
+      Plan 2.5 P6-followup-styling: rounded-xl (matches the brand square
+      in SidebarHeader), p-2 padding, hover background — replaces the
+      sharper rounded-[var(--p-border-radius)] / px-[10px] py-[8px] state.
+      Collapsed variant centres the avatar only, hiding the name and
+      chevron, so the collapsed rail reads as a vertical mirror: brand
+      square at the top, avatar square at the bottom.
+    -->
     <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="trigger flex w-full items-center gap-[10px] rounded-xl border border-transparent bg-transparent p-2 text-[var(--p-text-color)] transition-colors duration-150 hover:bg-[var(--p-content-hover-background)]"
       :class="[
         collapsed ? 'justify-center' : '',
       ]"
       aria-haspopup="true"
       @click="toggle"
     >
-      <!-- Logo square (gradient background is bespoke: dynamic hex pair cannot be a static Tailwind class — RFC §7.4 justified inline-style) -->
+      <!-- Avatar square — shared treatment with SidebarHeader logo (h-8 w-8 rounded-xl). Gradient background is bespoke per organisation (dynamic hex pair, RFC §7.4 inline-style). -->
       <span
         v-if="current"
-        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]"
+        class="ws-logo ws-logo-square w-8 h-8 flex-shrink-0 rounded-xl 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 }}
@@ -156,7 +164,7 @@ function inviteUser(): void {
       <!-- 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]"
+        class="meta flex flex-1 min-w-0 flex-col text-left leading-[1.2]"
       >
         <span class="name truncate text-[13.5px] font-semibold text-[var(--p-text-color)]">
           {{ current.name }}