feat: add multi-gateway management with auto port detection

- Add GatewayManager for multi-profile gateway lifecycle management
- Auto-detect running gateways on startup via PID + health check
- Port conflict detection: check managed gateways, allocated ports, and
  system-level port availability (TCP bind test)
- Two-phase startup: sequential port resolution, parallel process launch
- Use `gateway start/restart` on normal systems, `gateway run --replace`
  on WSL/Docker
- Wait for health check before returning start/stop responses
- Add Gateways page with card-based layout showing profile status
- Reorganize sidebar navigation into collapsible groups
- Hide API server settings (now auto-managed by GatewayManager)
- Profile switch reloads page; Ctrl+C no longer stops gateways
- Remove redundant ensureApiServerConfig from index.ts and profiles.ts

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

packages/client/src/router/index.ts

@@ -55,6 +55,11 @@ const router = createRouter({
       name: 'hermes.settings',
       component: () => import('@/views/hermes/SettingsView.vue'),
     },
+    {
+      path: '/hermes/gateways',
+      name: 'hermes.gateways',
+      component: () => import('@/views/hermes/GatewaysView.vue'),
+    },
     {
       path: '/hermes/channels',
       name: 'hermes.channels',