fix: GIFs, topic display, formatting toolbar, Copy Link in Invite, support URL

- RoomInput: GIF domain check uses endsWith('.giphy.com') — handles all
  Giphy CDN shards; all silent failure paths now show user-facing error
- RoomProfile: topic plain-text field is now HTML-stripped (no markdown
  syntax visible in header); formatting toolbar (B/I/S/code) above the
  textarea wraps selected text with correct markdown syntax
- InviteUserPrompt: Copy Link button added to dialog header with
  'Copied!' confirmation; removed Copy Link from both three-dot menus
- RoomViewHeader/RoomNavItem: unused copy-link imports removed
- nginx (live): support_page URL updated from lotusguild.org →
  matrix.lotusguild.org

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

src/app/features/room-nav/RoomNavItem.tsx

@@ -36,16 +36,12 @@ import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { useRoomUnread } from '../../state/hooks/unread';
 import { roomToUnreadAtom } from '../../state/room/roomToUnread';
 import { getPowersLevelFromMatrixEvent, usePowerLevels } from '../../hooks/usePowerLevels';
-import { copyToClipboard } from '../../utils/dom';
 import { markAsRead } from '../../utils/notifications';
 import { UseStateProvider } from '../../components/UseStateProvider';
 import { LeaveRoomPrompt } from '../../components/leave-room-prompt';
 import { useRoomTypingMember } from '../../hooks/useRoomTypingMembers';
 import { TypingIndicator } from '../../components/typing-indicator';
 import { stopPropagation } from '../../utils/keyboard';
-import { getMatrixToRoom } from '../../plugins/matrix-to';
-import { getCanonicalAliasOrRoomId, isRoomAlias } from '../../utils/matrix';
-import { getViaServers } from '../../plugins/via-servers';
 import { useMediaAuthentication } from '../../hooks/useMediaAuthentication';
 import { useSetting } from '../../state/hooks/settings';
 import { settingsAtom } from '../../state/settings';
@@ -225,13 +221,6 @@ const RoomNavItemMenu = forwardRef<HTMLDivElement, RoomNavItemMenuProps>(
       setInvitePrompt(true);
     };
 
-    const handleCopyLink = () => {
-      const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, room.roomId);
-      const viaServers = isRoomAlias(roomIdOrAlias) ? undefined : getViaServers(room);
-      copyToClipboard(getMatrixToRoom(roomIdOrAlias, viaServers));
-      requestClose();
-    };
-
     const handleRoomSettings = () => {
       openRoomSettings(room.roomId, space?.roomId);
       requestClose();
@@ -298,16 +287,6 @@ const RoomNavItemMenu = forwardRef<HTMLDivElement, RoomNavItemMenuProps>(
               Invite
             </Text>
           </MenuItem>
-          <MenuItem
-            onClick={handleCopyLink}
-            size="300"
-            after={<Icon size="100" src={Icons.Link} />}
-            radii="300"
-          >
-            <Text style={{ flexGrow: 1 }} as="span" size="T300" truncate>
-              Copy Link
-            </Text>
-          </MenuItem>
           <MenuItem
             onClick={() => {
               requestClose();