chore: upgrade TypeScript to 6.0.3 and modernize tsconfig

- typescript 5.9.3 to 6.0.3
- moduleResolution Node to bundler (correct for Vite projects)
- target/lib ES2016 to ES2020 (enables flatMap, Promise.allSettled)
- Fix global to globalThis in initMatrix.ts (browser env)
- Fix EventEmitter default to named import in CallControl.ts

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

src/client/initMatrix.ts

@@ -17,12 +17,12 @@ export const IDB_VERSION_CONFLICT = 'IDB_VERSION_CONFLICT';
 
 export const initClient = async (session: Session): Promise<MatrixClient> => {
   const indexedDBStore = new IndexedDBStore({
-    indexedDB: global.indexedDB,
-    localStorage: global.localStorage,
+    indexedDB: globalThis.indexedDB,
+    localStorage: globalThis.localStorage,
     dbName: 'web-sync-store',
   });
 
-  const legacyCryptoStore = new IndexedDBCryptoStore(global.indexedDB, 'crypto-store');
+  const legacyCryptoStore = new IndexedDBCryptoStore(globalThis.indexedDB, 'crypto-store');
 
   const mx = createClient({
     baseUrl: session.baseUrl,