v0.0.5: WebSocket real-time messaging

Server:
- WS endpoint: /v1/ws/:fingerprint
- Connection registry in AppState (fingerprint → WS senders)
- On connect: flushes queued DB messages, then pushes in real-time
- send_message: pushes to WS if connected, falls back to DB queue
- Auto-cleanup on disconnect
- WS accepts both binary and JSON text frames for sending

Web client:
- Replaces 2-second HTTP polling with persistent WebSocket
- Auto-reconnects on disconnect (3-second backoff)
- Sends via WS when connected, HTTP fallback
- Messages arrive instantly (no polling delay)
- "Real-time connection established" shown on connect

HTTP polling still works:
- CLI recv command uses HTTP (unchanged)
- Web falls back to HTTP if WS fails
- Mules/scripts can still use HTTP API

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/crates/warzone-server/Cargo.toml

@@ -22,5 +22,6 @@ chrono.workspace = true
 hex.workspace = true
 base64.workspace = true
 rand.workspace = true
+futures-util = "0.3"
 ed25519-dalek.workspace = true
 bincode.workspace = true