feat(dashboard): simplify navigation — frequency-based IA

The sidebar had 22 items in 5 accordion groups, all defaulting closed:
first visit showed five vague headers and zero destinations, there was
no Dashboard/Home link at all, and rare pages (taxes, subscription) had
equal weight with POS. Restructured around usage frequency:

- Flat primary (always visible, no header): Dashboard, POS, Tables,
  Kitchen, Queue, Reservations, Menu, Reports
- Two collapsible groups: Customers & marketing (crm, coupons, sms,
  reviews, discover) and Café management (inventory, expenses, shifts,
  taxes, hr, branches)
- Footer utility icons: settings, subscription, support
- Removed "notifications" from the nav (duplicate of the topbar bell)

Other fixes folded in:
- Deleted [locale]/page.tsx which redirected "/" to /pos — it made the
  POS exit button a no-op loop and left OverviewScreen unreachable.
  "/" now renders the overview home; login still lands on /pos.
- Branch gating moved from group-level to an item whitelist
  (BRANCH_ALLOWED_NAV_KEYS) — also closes the hole where branch
  accounts could deep-link to /reports etc. past the RouteGuard.
- RouteGuard now checks footer items too (subscription stays gated).
- revalidate=300 on the locale layout: Next emitted s-maxage=31536000
  and the WCDN edge kept serving year-old HTML shells after deploys.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.claude/launch.json

@@ -6,6 +6,20 @@
       "runtimeExecutable": "dotnet",
       "runtimeArgs": ["run", "--project", "F:/Projects/DrSousan/DrSousan.Api", "--urls", "http://localhost:5000"],
       "port": 5000
+    },
+    {
+      "name": "meezi-website",
+      "runtimeExecutable": "node",
+      "runtimeArgs": ["node_modules/next/dist/bin/next", "dev", "-p", "3013"],
+      "cwd": "web/website",
+      "port": 3013
+    },
+    {
+      "name": "meezi-dashboard",
+      "runtimeExecutable": "node",
+      "runtimeArgs": ["node_modules/next/dist/bin/next", "dev", "-p", "3015"],
+      "cwd": "web/dashboard",
+      "port": 3015
     }
   ]
 }