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/features/room/message/Reactions.tsx

@@ -202,7 +202,7 @@ export const Reactions = as<'div', ReactionsProps>(
         )}
         {reactions.length > 0 && (
           <Overlay
-            onContextMenu={(evt: any) => {
+            onContextMenu={(evt: React.MouseEvent) => {
               evt.stopPropagation();
             }}
             open={!!viewer}