fix: upgrade matrix-js-sdk 38.2.0 -> 41.5.0 with API compat fixes

- sessionMembershipsForRoom() removed in v41 (was synchronous, static)
- Replacement: read session.memberships directly (always up-to-date, sync)
  - useCall.ts: useCallMembers reads session.memberships
  - useCallEmbed.ts: createCallEmbed reads rtcSession.memberships
  - CallEmbedProvider.tsx: inline check on session.memberships
- Remove unused MatrixRTCSession import from CallEmbedProvider
- clearLoginData: also unregisters service workers and clears SW caches

src/client/initMatrix.ts

@@ -88,6 +88,15 @@ export const clearLoginData = async () => {
     }
   });
 
+  // Unregister service workers so stale caches don't interfere after a reset
+  if ('serviceWorker' in navigator) {
+    const regs = await navigator.serviceWorker.getRegistrations();
+    await Promise.all(regs.map((r) => r.unregister()));
+    const cacheNames = await caches.keys();
+    await Promise.all(cacheNames.map((c) => caches.delete(c)));
+  }
+
   window.localStorage.clear();
   window.location.reload();
 };
+