chore(lint): retire 19 explicit anys, ratchet to 49 warnings (#210)

Event handlers typed as React.MouseEvent, join errors as Error, the
service-worker session setter as strings, the UIA policy map and the
webkitAudioContext probe as narrow shapes. No behaviour change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/utils/lotusDenoiseUtils.ts

@@ -68,7 +68,9 @@ export const isMLDenoiseSupported = (): boolean => {
   // 1. AudioContext/webkitAudioContext (Web Audio API)
   // 2. AudioWorklet (Real-time processing in a background thread)
   // 3. getUserMedia (Microphone access)
-  const hasAudioContext = !!(window.AudioContext || (window as any).webkitAudioContext);
+  const hasAudioContext = !!(
+    window.AudioContext || (window as Window & { webkitAudioContext?: unknown }).webkitAudioContext
+  );
   // Use `typeof` rather than `!!AudioWorkletNode`: on a browser that has
   // AudioContext but no AudioWorkletNode binding (older Safari/Edge), a bare
   // reference throws ReferenceError, making this feature-detection helper throw