v0.0.40: reliability — call reload, ETH cache prefill, 10 server tests

Call state reload on restart:
- Loads Ringing/Active calls from sled into active_calls on startup
- Expires calls older than 24h automatically

TUI sender ETH cache prefill:
- prefill_eth_cache() resolves all known contacts on poll_loop start
- First message from known contacts now shows ETH address immediately

Server integration tests (10 new):
- push_to_client offline/online
- register_ws + connection cap (5 max)
- is_online + device_count
- kick_device + revoke_all_except
- deliver_or_queue offline/online
- call state lifecycle
- list_devices

155 tests passing (was 135)

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 = "0.0.39"
+version = "0.0.40"
 edition = "2021"
 license = "MIT"
 description = "Core crypto & wire protocol for featherChat (Warzone messenger)"