feat(appshell): add org-switcher card and bump sidebar width to w-72

Introduces SidebarHeader.vue — a PrimeVue-only org-switcher that
replaces the centered Crewli wordmark at the top of the sidebar. The
component mirrors the legacy Vuetify OrganisationSwitcher (avatar with
org initials, organisation name, plan-tier placeholder, dropdown
chevron, PrimeVue Menu of available orgs) but cannot reuse it
directly per the R-10 layout-shell-isolation invariant.

Plan-tier shows a hardcoded "Pro" placeholder until the backend
Organisation resource exposes a plan field — tracked separately, not
in F3.5 scope. When the user has no active organisation (portal
users, fresh super_admin), the component degrades to the original
title block so PortalLayout continues to read "Crewli Portal".

Desktop sidebar width bumped w-64 → w-72 (256 → 288 px) to give the
org-switcher card breathing room and accommodate the user-info card
arriving in B3. Mobile Drawer width bumped 16rem → 18rem to match.

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

apps/app/src/layouts/components/AppShell.vue

@@ -94,10 +94,8 @@ function toggleUserMenu(event: Event) {
 <template>
   <div class="crewli-app-shell flex min-h-screen">
     <!-- Desktop sidebar (lg+) -->
-    <aside class="hidden lg:flex w-64 flex-col border-r border-surface-200 bg-surface-0">
-      <div class="flex h-16 items-center justify-center border-b border-surface-200">
-        <span class="text-xl font-semibold text-primary-500">{{ title }}</span>
-      </div>
+    <aside class="hidden lg:flex w-72 flex-col border-r border-surface-200 bg-surface-0">
+      <SidebarHeader :title="title" />
       <nav class="flex-1 overflow-y-auto p-3">
         <template
           v-for="(item, idx) in navItems"
@@ -130,12 +128,12 @@ function toggleUserMenu(event: Event) {
       v-model:visible="mobileNavOpen"
       position="left"
       class="lg:hidden"
-      :pt="{ root: { style: { width: '16rem' } } }"
+      :pt="{ root: { style: { width: '18rem' } }, header: { class: 'p-0' } }"
     >
       <template #header>
-        <span class="text-lg font-semibold text-primary-500">{{ title }}</span>
+        <SidebarHeader :title="title" />
       </template>
-      <nav class="flex flex-col">
+      <nav class="flex flex-col p-3">
         <template
           v-for="(item, idx) in navItems"
           :key="idx"