feat: Phase 1c — Platform Admin Dashboard

Full super-admin dashboard for SaaS platform management:

Backend (10 files):
- Migration 003: Add is_super_admin column to users table
- JWT Claims: Carry is_super_admin through access tokens
- SuperAdmin extractor: Axum FromRequestParts that rejects non-admins (403)
- Admin API module: 10 endpoints behind /api/admin/*
  - GET /stats (KPIs: licenses, users, MRR, servers, signups)
  - GET/POST /licenses (paginated, filterable, manual generation)
  - GET/PATCH /licenses/:id (detail view, revoke/activate)
  - GET /subscriptions (module sub list with MRR breakdown)
  - GET/PATCH /users (paginated, toggle admin, disable accounts)
  - GET /servers (fleet overview across all licenses)
  - GET /health (DB pool, NATS status, table row counts)
- Bootstrap updated: first user gets is_super_admin = true

Frontend (8 files):
- 5 admin views in src/views/platform-admin/
- DashboardLayout: "Platform" nav section (gated on isSuperAdmin)
- Router: /admin/* routes with superAdmin meta guard
- Auth store: isSuperAdmin computed property
- Types: is_super_admin on User interface

Build: 80 chunks, zero TS errors, clean production build.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/components/layout/DashboardLayout.vue

@@ -18,6 +18,10 @@ import {
   Package,
   Settings,
   LogOut,
+  Shield,
+  Key,
+  CreditCard,
+  Network,
 } from 'lucide-vue-next'
 
 const route = useRoute()
@@ -42,6 +46,14 @@ const navItems = [
   { name: 'Settings', path: '/settings', icon: Settings },
 ]
 
+const adminNavItems = [
+  { name: 'Admin Home', path: '/admin', icon: Shield },
+  { name: 'Licenses', path: '/admin/licenses', icon: Key },
+  { name: 'Subscriptions', path: '/admin/subscriptions', icon: CreditCard },
+  { name: 'Users', path: '/admin/users', icon: Users },
+  { name: 'Server Fleet', path: '/admin/servers', icon: Network },
+]
+
 function isActive(path: string): boolean {
   if (path === '/') return route.path === '/'
   return route.path.startsWith(path)
@@ -99,6 +111,29 @@ function handleLogout() {
           <component :is="item.icon" class="w-4 h-4" />
           {{ item.name }}
         </RouterLink>
+
+        <!-- Platform Admin Section (super-admin only) -->
+        <template v-if="auth.isSuperAdmin">
+          <div class="mt-4 mb-2 px-4">
+            <div class="flex items-center gap-2">
+              <div class="flex-1 border-t border-neutral-700" />
+              <span class="text-[10px] font-semibold uppercase tracking-widest text-oxide-500">Platform</span>
+              <div class="flex-1 border-t border-neutral-700" />
+            </div>
+          </div>
+          <RouterLink
+            v-for="item in adminNavItems"
+            :key="item.path"
+            :to="item.path"
+            class="flex items-center gap-3 px-4 py-2 mx-2 rounded-lg text-sm transition-colors"
+            :class="isActive(item.path)
+              ? 'bg-oxide-500/10 text-oxide-400'
+              : 'text-neutral-400 hover:bg-neutral-800 hover:text-neutral-200'"
+          >
+            <component :is="item.icon" class="w-4 h-4" />
+            {{ item.name }}
+          </RouterLink>
+        </template>
       </nav>
 
       <!-- User -->