- Adds `js/services/storageService.js` to manage encrypted connection credentials.
- Implements AES-GCM encryption for payloads using a random Master Key.
- Implements NIP-04/NIP-44 encryption for the Master Key using the user's Nostr signer.
- Provides public API for saving, retrieving, and listing connections.
- Persists data to `bitvid-storage` IndexedDB.