feat: GIF previews, room context menu, policy lists, mention pulse, collapsible messages, send animation, D&D fix

P3-5: Giphy/Tenor URL preview cards — full-width thumbnail from og:image
mxc URL, GIF badge overlay, site badge + title footer; GifCard shared by
both; BadgeGiphy (teal) and BadgeTenor (blue) CSS classes

P3-9: Policy list viewer — read-only panel in Room Settings + Space
Settings (admin/50+ PL only); enter room ID or alias; tabs for Users /
Rooms / Servers; glob pattern warning color; Ban badge; entity + reason

P5-8: Mention highlight pulse — 0.6s scale+glow keyframe on incoming
@mention messages; prefers-reduced-motion aware; only fires on new
incoming messages (isNewRef), not on history load; onAnimationEnd cleanup

P5-19: Collapsible long messages — ResizeObserver clamps text bodies
>320px with gradient fade + "Read more ↓" / "Show less ↑" button; resets
on eventId change; skips images/video/audio/file; smooth CSS transition

P5-23: Message send animation — own messages fade+scale in (0.97→1,
0.4→1 opacity, 150ms ease-out); prefers-reduced-motion aware; one-shot
via isNewRef + onAnimationEnd clear

P5-26: Room context menu — Copy Link (matrix.to URL, 1.5s Copied!
feedback), Mute with duration (15m/1h/8h/24h/indefinite, localStorage
timer key io.lotus.mute_timers), Mark as read; Icons.Link + Icons.BellMute

BUG D&D: dragCounter ref replaces fragile dragState machine — enter
increments, leave decrements (hides at 0), drop resets to 0; fixes
spurious dragleave from child element boundary crossings

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

src/app/features/room/RoomTimeline.tsx

@@ -1132,6 +1132,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
                 htmlReactParserOptions={htmlReactParserOptions}
                 linkifyOpts={linkifyOpts}
                 outlineAttachment={messageLayout === MessageLayout.Bubble}
+                eventId={mEventId}
               />
             )}
           </Message>
@@ -1241,6 +1242,7 @@ export function RoomTimeline({ room, eventId, roomInputRef, editor }: RoomTimeli
                       htmlReactParserOptions={htmlReactParserOptions}
                       linkifyOpts={linkifyOpts}
                       outlineAttachment={messageLayout === MessageLayout.Bubble}
+                      eventId={mEventId}
                     />
                   );
                 }