feat: resolve handle-based actor param in feed layer + APNs improvements
Add resolveHandleToDid to db.ts and use it in executeFeed to automatically
resolve handle-based actor params to DIDs before passing to feed handlers.
Also improve APNs HTTP/2 session with connection logging and request timeout handling.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>