fix: address confirmed bugs from LOTUS_BUGS.md audit

- useFileDrop: reset drag overlay when mouse leaves browser window
  (relatedTarget === null signals viewport exit, counter was getting stuck)
- useDeviceVerificationStatus: add member count to useMemo deps so new
  room members' devices get checked, not just initial joined members
- index.css: define --bg-surface-variant used by VoiceMessageRecorder,
  MessageSearch, SearchFilters, UserRoomProfile (was falling back to transparent)
- syntaxHighlight: fix Python inline comments — # after space/tab was
  treated as plain text; only start-of-line was recognised
- usePresenceUpdater: replace internal baseUrl cast with mx.getHomeserverUrl()
- useLocalMessageSearch: scan all linked timelines via getUnfilteredTimelineSet()
  not just the live window, so scrolled-back history is included in E2EE search
- RoomViewHeader: show search button in encrypted rooms — local search is
  implemented and handles them; the guard was a holdover from before it existed
- recent-emoji: return emojis in recency order (array is already unshifted on
  use) instead of sorting by total usage count

Skipped: media gallery memory leak (needs virtualization refactor),
bookmark race condition (needs queue/lock), Night Light portal coverage
(position:fixed already covers full viewport — not a real bug).

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

src/app/plugins/recent-emoji.ts

@@ -16,7 +16,6 @@ export const getRecentEmojis = (mx: MatrixClient, limit?: number): IEmoji[] => {
   if (!Array.isArray(recentEmoji)) return [];
 
   return recentEmoji
-    .sort((e1, e2) => e2[1] - e1[1])
     .slice(0, limit)
     .reduce<IEmoji[]>((list, [unicode]) => {
       const emoji = emojis.find((e) => e.unicode === unicode);