Introduces a secure peer-to-peer cache sharing system using HMAC-SHA256 request signatures and Fernet (AES-128-CBC) response encryption.
- New peer_keys table for per-peer credential management (key_id, secret)
- New /api/peer/check endpoint returns encrypted debrid availability data
- New /api/peer/items endpoint returns encrypted torrent metadata
- Rate limiting per peer key with configurable limits and windows
- Admin UI for creating, viewing, revoking, and deleting peer keys
- Peer cache enrichment integrated into BaseDebrid L2.5 lookup pipeline
- StremThruDebrid override with cross-service PG L2 check + peer cache
- Removed old /api/share/cache endpoint (replaced by /api/peer/*)
- Added cryptography package dependency
BREAKING CHANGE: The /api/share/cache endpoint has been removed and replaced with /api/peer/check. Clients must update to use HMAC authentication with X-Peer-Key-Id, X-Peer-Timestamp, and X-Peer-Signature headers.
