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/components/AnimatedOutlet.tsx

@@ -1,16 +1,53 @@
-import React from 'react';
+import React, { useMemo } from 'react';
 import { Outlet, useLocation } from 'react-router-dom';
 
+const decodeSegment = (segment: string): string => {
+  let decoded = segment;
+  try {
+    let next = decodeURIComponent(decoded);
+    while (next !== decoded) {
+      decoded = next;
+      next = decodeURIComponent(decoded);
+    }
+  } catch {
+    // keep partially decoded value
+  }
+  return decoded;
+};
+
 /**
- * Wrapper for Outlet that adds route-based animation
- * Forces remount on route change by using location as key
+ * Room routes are `:roomIdOrAlias/:eventId?/`. Jumping to an event (or clearing it)
+ * changes the pathname but not the room — keep the outlet mounted so we don't replay
+ * the route enter animation or remount drawers like Shared Media.
+ *
+ * Path segments are decoded so `!room:server` and `%21room%3Aserver` share a key.
+ */
+const getOutletTransitionKey = (pathname: string): string => {
+  const segments = pathname.split('/').filter(Boolean).map(decodeSegment);
+  if (segments.length === 0) return pathname;
+
+  // Matrix event IDs start with `$`
+  if (segments[segments.length - 1].startsWith('$')) {
+    segments.pop();
+  }
+
+  return `/${segments.join('/')}/`;
+};
+
+/**
+ * Wrapper for Outlet that adds route-based animation.
+ * Remounts (and animates) when leaving a room / switching rooms, not on same-room event hops.
  */
 export function AnimatedOutlet() {
   const location = useLocation();
-  
+  const transitionKey = useMemo(
+    () => getOutletTransitionKey(location.pathname),
+    [location.pathname]
+  );
+
   return (
     <div
-      key={location.pathname}
+      key={transitionKey}
       data-route-transition="true"
       style={{
         flex: 1,