refactor: rename features to room-based directory structure

- Rename features/dashboard → features/front_hall
- Update routes: /, /control-room, /parlor, /settings
- Update navigation to 4 rooms (removed chat tab - will be omnipresent dock)
- Add docs/UI_LAYOUT.md with wireframes and responsive specs
- Update ARCHITECTURE.md and PLAN.md to reflect room structure

Directory structure now mirrors "Rooms of the Estate" UI navigation:
- front_hall/ (dashboard)
- control_room/ (infrastructure - containers, stacks, etc.)
- parlor/ (home automation)
- library/ (future)
- study/ (future, hidden)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/routing/app_router.dart

@@ -3,17 +3,17 @@ import 'package:go_router/go_router.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 
 import '../shared/layouts/app_scaffold.dart';
-import '../features/dashboard/presentation/pages/dashboard_page.dart';
+import '../features/front_hall/presentation/pages/front_hall_page.dart';
 
 part 'app_router.g.dart';
 
 /// Route paths as constants.
 abstract class AppRoutes {
-  static const dashboard = '/';
-  static const chat = '/chat';
-  static const containers = '/containers';
-  static const containerDetail = '/containers/:id';
-  static const housekeeping = '/housekeeping';
+  static const frontHall = '/';
+  static const controlRoom = '/control-room';
+  static const containers = '/control-room/containers';
+  static const containerDetail = '/control-room/containers/:id';
+  static const parlor = '/parlor';
   static const settings = '/settings';
 }
 
@@ -21,43 +21,46 @@ abstract class AppRoutes {
 @riverpod
 GoRouter appRouter(AppRouterRef ref) {
   return GoRouter(
-    initialLocation: AppRoutes.dashboard,
+    initialLocation: AppRoutes.frontHall,
     debugLogDiagnostics: true,
     routes: [
       ShellRoute(
         builder: (context, state, child) => AppScaffold(child: child),
         routes: [
           GoRoute(
-            path: AppRoutes.dashboard,
-            name: 'dashboard',
-            builder: (context, state) => const DashboardPage(),
+            path: AppRoutes.frontHall,
+            name: 'frontHall',
+            builder: (context, state) => const FrontHallPage(),
           ),
           GoRoute(
-            path: AppRoutes.chat,
-            name: 'chat',
-            builder: (context, state) => const _PlaceholderPage(title: 'Chat'),
-          ),
-          GoRoute(
-            path: AppRoutes.containers,
-            name: 'containers',
+            path: AppRoutes.controlRoom,
+            name: 'controlRoom',
             builder: (context, state) =>
-                const _PlaceholderPage(title: 'Containers'),
+                const _PlaceholderPage(title: 'Control Room'),
             routes: [
               GoRoute(
-                path: ':id',
-                name: 'containerDetail',
-                builder: (context, state) {
-                  final id = state.pathParameters['id']!;
-                  return _PlaceholderPage(title: 'Container: $id');
-                },
+                path: 'containers',
+                name: 'containers',
+                builder: (context, state) =>
+                    const _PlaceholderPage(title: 'Containers'),
+                routes: [
+                  GoRoute(
+                    path: ':id',
+                    name: 'containerDetail',
+                    builder: (context, state) {
+                      final id = state.pathParameters['id']!;
+                      return _PlaceholderPage(title: 'Container: $id');
+                    },
+                  ),
+                ],
               ),
             ],
           ),
           GoRoute(
-            path: AppRoutes.housekeeping,
-            name: 'housekeeping',
+            path: AppRoutes.parlor,
+            name: 'parlor',
             builder: (context, state) =>
-                const _PlaceholderPage(title: 'Housekeeping'),
+                const _PlaceholderPage(title: 'Parlor'),
           ),
           GoRoute(
             path: AppRoutes.settings,