Add Shared Media drawer and harden same-room navigation.

Widen the media panel, support skinny full-page mode, keep jump-to-latest and return-to-previous reliable, and stop same-room event jumps from remounting the outlet or yanking the sidebar.

src/app/hooks/useRoomNavigate.ts

@@ -1,5 +1,5 @@
 import { useCallback } from 'react';
-import { NavigateOptions, useNavigate } from 'react-router-dom';
+import { NavigateOptions, useLocation, useNavigate } from 'react-router-dom';
 import { useAtomValue } from 'jotai';
 import { getCanonicalAliasOrRoomId } from '../utils/matrix';
 import {
@@ -7,21 +7,25 @@ import {
   getHomeRoomPath,
   getSpacePath,
   getSpaceRoomPath,
+  withRoomEventId,
 } from '../pages/pathUtils';
 import { useMatrixClient } from './useMatrixClient';
 import { getOrphanParents, guessPerfectParent, isSpace } from '../utils/room';
 import { roomToParentsAtom } from '../state/room/roomToParents';
 import { mDirectAtom } from '../state/mDirectList';
+import { useSelectedRoom } from './router/useSelectedRoom';
 import { useSelectedSpace } from './router/useSelectedSpace';
 import { settingsAtom } from '../state/settings';
 import { useSetting } from '../state/hooks/settings';
 
 export const useRoomNavigate = () => {
   const navigate = useNavigate();
+  const location = useLocation();
   const mx = useMatrixClient();
   const roomToParents = useAtomValue(roomToParentsAtom);
   const mDirects = useAtomValue(mDirectAtom);
   const spaceSelectedId = useSelectedSpace();
+  const selectedRoomId = useSelectedRoom();
   const [developerTools] = useSetting(settingsAtom, 'developerTools');
 
   const navigateSpace = useCallback(
@@ -34,6 +38,14 @@ export const useRoomNavigate = () => {
 
   const navigateRoom = useCallback(
     (roomId: string, eventId?: string, opts?: NavigateOptions) => {
+      // Already viewing this room — keep the current home/direct/space URL and only
+      // change the event id. Otherwise guessPerfectParent can yank the sidebar to
+      // wherever the room "belongs".
+      if (selectedRoomId === roomId) {
+        navigate(withRoomEventId(location.pathname, eventId), opts);
+        return;
+      }
+
       const room = mx.getRoom(roomId);
       const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, roomId);
       const openSpaceTimeline = developerTools && spaceSelectedId === roomId;
@@ -68,7 +80,16 @@ export const useRoomNavigate = () => {
 
       navigate(getHomeRoomPath(roomIdOrAlias, eventId), opts);
     },
-    [mx, navigate, spaceSelectedId, roomToParents, mDirects, developerTools]
+    [
+      mx,
+      navigate,
+      location.pathname,
+      selectedRoomId,
+      spaceSelectedId,
+      roomToParents,
+      mDirects,
+      developerTools,
+    ]
   );
 
   return {