Add dynamic privacy policy notification with API fetch

Implements fetching the privacy policy from the BetterSEQTA+ API and displays a notification if the policy has been updated. Adds sanitization for HTML content, updates settings state to track last shown timestamp, and provides a manual trigger in settings. Refactors notification logic for improved security and maintainability.

src/types/storage.ts

@@ -31,6 +31,7 @@ export interface SettingsState {
   transparencyEffects: boolean;
   justupdated?: boolean;
   privacyStatementShown?: boolean;
+  privacyStatementLastUpdated?: string;
   timeFormat?: string;
   animations: boolean;
   defaultPage: string;