v0.0.36: web call UI — call/accept/reject/hangup with signaling

Web client:
- Call bar between header and messages (hidden when idle)
- Call button appears when peer is set (not group)
- Incoming call: pulsing notification + Accept/Reject buttons
- Call states: idle → calling → ringing → active
- /call, /accept, /reject, /hangup slash commands
- CallSignal sent via WS binary frames (same as messages)
- handleCallSignal processes Offer/Answer/Hangup/Reject/Ringing/Busy
- Vibration on incoming call (mobile)
- create_call_signal WASM import wired up

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

warzone/crates/warzone-protocol/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "warzone-protocol"
-version = "0.0.35"
+version = "0.0.36"
 edition = "2021"
 license = "MIT"
 description = "Core crypto & wire protocol for featherChat (Warzone messenger)"