feat: room search, room options sheet, .htaccess for E2EE

- Rooms screen: inline search filter with toggle — replaces the no-op button
- Chat screen: room options sheet — member list, invite, leave room
- rooms_repository: remove debug prints
- web/.htaccess: COOP+COEP headers for SharedArrayBuffer / LiveKit E2EE worker
  (was on production but missing from source; adds it to build output automatically)

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

lib/features/rooms/presentation/rooms_screen.dart

@@ -1,4 +1,4 @@
-// Version: 1.3.0 | Created: 2026-04-01 | Updated: 2026-04-11
+// Version: 1.4.0 | Created: 2026-04-01 | Updated: 2026-04-27
 // Main rooms list screen with bottom navigation.
 
 import 'package:flutter/material.dart';
@@ -22,6 +22,25 @@ class RoomsScreen extends ConsumerStatefulWidget {
 
 class _RoomsScreenState extends ConsumerState<RoomsScreen> {
   int _selectedIndex = 0;
+  bool _searchActive = false;
+  String _searchQuery = '';
+  final _searchController = TextEditingController();
+
+  @override
+  void dispose() {
+    _searchController.dispose();
+    super.dispose();
+  }
+
+  void _toggleSearch() {
+    setState(() {
+      _searchActive = !_searchActive;
+      if (!_searchActive) {
+        _searchQuery = '';
+        _searchController.clear();
+      }
+    });
+  }
 
   static const _destinations = [
     NavigationDestination(
@@ -53,7 +72,7 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
 
   Widget _buildBody() {
     return switch (_selectedIndex) {
-      0 => const _RoomListBody(),
+      0 => _RoomListBody(searchQuery: _searchQuery),
       1 => const SpacesScreen(embedded: true),
       2 => const ProfileScreen(embedded: true),
       3 => const ConferenceTab(),
@@ -67,20 +86,29 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
     return Scaffold(
       appBar: _selectedIndex == 0
           ? AppBar(
-              title: const Text('M8Chat'),
+              title: _searchActive
+                  ? TextField(
+                      controller: _searchController,
+                      autofocus: true,
+                      decoration: const InputDecoration(
+                        hintText: 'Search rooms...',
+                        border: InputBorder.none,
+                      ),
+                      onChanged: (v) => setState(() => _searchQuery = v),
+                    )
+                  : const Text('M8Chat'),
               actions: [
                 IconButton(
-                  icon: const Icon(Icons.search),
-                  tooltip: 'Search rooms',
-                  onPressed: () {
-                    // Phase 2: room search
-                  },
-                ),
-                IconButton(
-                  icon: const Icon(Icons.edit_square),
-                  tooltip: 'New message',
-                  onPressed: () => showUserSearchDialog(context),
+                  icon: Icon(_searchActive ? Icons.close : Icons.search),
+                  tooltip: _searchActive ? 'Cancel search' : 'Search rooms',
+                  onPressed: _toggleSearch,
                 ),
+                if (!_searchActive)
+                  IconButton(
+                    icon: const Icon(Icons.edit_square),
+                    tooltip: 'New message',
+                    onPressed: () => showUserSearchDialog(context),
+                  ),
               ],
             )
           : null,
@@ -96,7 +124,9 @@ class _RoomsScreenState extends ConsumerState<RoomsScreen> {
 }
 
 class _RoomListBody extends ConsumerWidget {
-  const _RoomListBody();
+  const _RoomListBody({this.searchQuery = ''});
+
+  final String searchQuery;
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
@@ -132,14 +162,39 @@ class _RoomListBody extends ConsumerWidget {
         ),
       ),
       data: (rooms) {
-        if (rooms.isEmpty) {
-          return const _EmptyRoomsState();
+        final filtered = searchQuery.trim().isEmpty
+            ? rooms
+            : rooms
+                .where((r) => r.displayName
+                    .toLowerCase()
+                    .contains(searchQuery.trim().toLowerCase()))
+                .toList();
+
+        if (filtered.isEmpty) {
+          return searchQuery.isNotEmpty
+              ? Center(
+                  child: Padding(
+                    padding: const EdgeInsets.all(32),
+                    child: Text(
+                      'No rooms match "$searchQuery".',
+                      textAlign: TextAlign.center,
+                      style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                            color: Theme.of(context)
+                                .colorScheme
+                                .onSurface
+                                .withAlpha(153),
+                          ),
+                    ),
+                  ),
+                )
+              : const _EmptyRoomsState();
         }
+
         return ListView.separated(
-          itemCount: rooms.length,
+          itemCount: filtered.length,
           separatorBuilder: (_, __) => const Divider(height: 1, indent: 72),
           itemBuilder: (context, index) {
-            final room = rooms[index];
+            final room = filtered[index];
             return RoomTile(
               room: room,
               onTap: () =>