chore: upgrade TypeScript 4.9 to 5.9, ESLint 8.29 to 8.57, @typescript-eslint 5 to 7

Resolves all TS2345/TS2347/TS7006 type errors introduced by stricter TypeScript 5.x.
Fix Icons.Settings to Icons.Setting, cast account data returns, fix implicit any.

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

src/app/hooks/useAccountData.ts

@@ -1,10 +1,13 @@
+import { MatrixEvent } from 'matrix-js-sdk';
 import { useState, useCallback } from 'react';
 import { useMatrixClient } from './useMatrixClient';
 import { useAccountDataCallback } from './useAccountDataCallback';
 
-export function useAccountData(eventType: string) {
+export function useAccountData(eventType: string): MatrixEvent | undefined {
   const mx = useMatrixClient();
-  const [event, setEvent] = useState(() => mx.getAccountData(eventType));
+  const [event, setEvent] = useState<MatrixEvent | undefined>(
+    () => (mx as any).getAccountData(eventType) as MatrixEvent | undefined,
+  );
 
   useAccountDataCallback(
     mx,