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/matrix-uia.ts

@@ -72,7 +72,10 @@ export const getLoginTermUrl = (params: UIAParams): string | undefined => {
     if (terms.policies === null) return undefined;
     if ('privacy_policy' in terms.policies && typeof terms.policies.privacy_policy === 'object') {
       if (terms.policies.privacy_policy === null) return undefined;
-      const langToPolicy = terms.policies.privacy_policy as Record<string, any>;
+      const langToPolicy = terms.policies.privacy_policy as Record<
+        string,
+        { url?: string } | undefined
+      >;
       const url = langToPolicy.en?.url;
       if (typeof url === 'string') return url;