Add Phase 5 dependencies (tokio-tungstenite, ciborium)
Phase 5 implements the subscription stage for com.atproto.label.subscribeLabels
with two-connection backfill+live-tail strategy.
Dependencies:
- bytes 1.10: byte buffer types for frame payloads
- ciborium 0.2: CBOR decoding for frame header and payload blocks
- futures-util 0.3: StreamExt for WebSocket frame iteration
- tokio-tungstenite 0.29 with rustls-tls-native-roots: WebSocket client
with native certificate validation (no OpenSSL coupling)
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>