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/RoomInput.tsx

@@ -538,23 +538,26 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
       async (gifUrl: string, w: number, h: number) => {
         setGifUploading(true);
         try {
-          // Only fetch from trusted Giphy CDN domains
-          const allowed = [
-            'media.giphy.com',
-            'i.giphy.com',
-            'media0.giphy.com',
-            'media1.giphy.com',
-            'media2.giphy.com',
-            'media3.giphy.com',
-            'media4.giphy.com',
-          ];
+          // Only fetch from trusted Giphy CDN domains (match any *.giphy.com subdomain)
           const { hostname } = new URL(gifUrl);
-          if (!allowed.includes(hostname)) return;
+          if (!hostname.endsWith('.giphy.com') && hostname !== 'giphy.com') {
+            setGifError('GIF source not trusted.');
+            setTimeout(() => setGifError(null), 4000);
+            return;
+          }
 
           const res = await fetch(gifUrl);
-          if (!res.ok) return;
+          if (!res.ok) {
+            setGifError('Failed to download GIF from Giphy.');
+            setTimeout(() => setGifError(null), 4000);
+            return;
+          }
           const contentType = res.headers.get('content-type') ?? '';
-          if (!contentType.startsWith('image/')) return;
+          if (!contentType.startsWith('image/')) {
+            setGifError('Unexpected GIF format. Please try another.');
+            setTimeout(() => setGifError(null), 4000);
+            return;
+          }
 
           const blob = await res.blob();
           if (blob.size > 20 * 1024 * 1024) {

src/app/features/room/RoomViewHeader.tsx

@@ -38,7 +38,7 @@ import { useSetting } from '../../state/hooks/settings';
 import { settingsAtom } from '../../state/settings';
 import { useSpaceOptionally } from '../../hooks/useSpace';
 import { getHomeSearchPath, getSpaceSearchPath, withSearchParam } from '../../pages/pathUtils';
-import { getCanonicalAliasOrRoomId, isRoomAlias, mxcUrlToHttp } from '../../utils/matrix';
+import { getCanonicalAliasOrRoomId, mxcUrlToHttp } from '../../utils/matrix';
 import { getStateEvents } from '../../utils/room';
 import { _SearchPathSearchParams } from '../../pages/paths';
 import * as css from './RoomViewHeader.css';
@@ -46,13 +46,10 @@ import { useRoomUnread } from '../../state/hooks/unread';
 import { usePowerLevelsContext } from '../../hooks/usePowerLevels';
 import { markAsRead } from '../../utils/notifications';
 import { roomToUnreadAtom } from '../../state/room/roomToUnread';
-import { copyToClipboard } from '../../utils/dom';
 import { LeaveRoomPrompt } from '../../components/leave-room-prompt';
 import { useRoomAvatar, useLocalRoomName, useRoomTopic } from '../../hooks/useRoomMeta';
 import { ScreenSize, useScreenSizeContext } from '../../hooks/useScreenSize';
 import { stopPropagation } from '../../utils/keyboard';
-import { getMatrixToRoom } from '../../plugins/matrix-to';
-import { getViaServers } from '../../plugins/via-servers';
 import { BackRouteHandler } from '../../components/BackRouteHandler';
 import { useMediaAuthentication } from '../../hooks/useMediaAuthentication';
 import { useRoomPinnedEvents } from '../../hooks/useRoomPinnedEvents';
@@ -107,13 +104,6 @@ const RoomMenu = forwardRef<HTMLDivElement, RoomMenuProps>(({ room, requestClose
     setInvitePrompt(true);
   };
 
-  const handleCopyLink = () => {
-    const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, room.roomId);
-    const viaServers = isRoomAlias(roomIdOrAlias) ? undefined : getViaServers(room);
-    copyToClipboard(getMatrixToRoom(roomIdOrAlias, viaServers));
-    requestClose();
-  };
-
   const openSettings = useOpenRoomSettings();
   const parentSpace = useSpaceOptionally();
   const handleOpenSettings = () => {
@@ -193,16 +183,6 @@ const RoomMenu = forwardRef<HTMLDivElement, RoomMenuProps>(({ room, requestClose
             </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>
         {!isServerNotice && (
           <MenuItem
             onClick={handleOpenSettings}