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/pages/pathUtils.ts

@@ -3,6 +3,7 @@ import {
   DIRECT_CREATE_PATH,
   DIRECT_PATH,
   DIRECT_ROOM_PATH,
+  DIRECT_SEARCH_PATH,
   DIRECT_NOTIFICATIONS_PATH,
   DIRECT_INVITES_PATH,
   EXPLORE_FEATURED_PATH,
@@ -121,6 +122,7 @@ export const getHomeRoomPath = (roomIdOrAlias: string, eventId?: string): string
 
 export const getDirectPath = (): string => DIRECT_PATH;
 export const getDirectCreatePath = (): string => DIRECT_CREATE_PATH;
+export const getDirectSearchPath = (): string => DIRECT_SEARCH_PATH;
 export const getDirectRoomPath = (roomIdOrAlias: string, eventId?: string): string => {
   const params = {
     roomIdOrAlias,
@@ -180,6 +182,28 @@ export const getSpaceRoomPath = (
   return generatePath(SPACE_ROOM_PATH, params);
 };
 
+/**
+ * Keep the current room URL (home / direct / space) and only add, replace, or clear
+ * the optional `$eventId` segment. Used so same-room jumps (media, permalinks) don't
+ * re-home the room into a different sidebar section.
+ */
+export const withRoomEventId = (pathname: string, eventId?: string): string => {
+  const parts = pathname.split('/').filter(Boolean);
+
+  if (parts.length > 0) {
+    const lastDecoded = decodeRouteParam(parts[parts.length - 1]);
+    if (lastDecoded?.startsWith('$')) {
+      parts.pop();
+    }
+  }
+
+  if (eventId) {
+    parts.push(encodeURIComponent(eventId));
+  }
+
+  return `/${parts.join('/')}/`;
+};
+
 export const getExplorePath = (): string => EXPLORE_PATH;
 export const getExploreFeaturedPath = (): string => EXPLORE_FEATURED_PATH;
 export const getExploreServerPath = (server: string): string => {