feat: friend list, bot API, ETH addressing, deep links, docs overhaul

Tier 1 — New features:
- E2E encrypted friend list: server stores opaque blob (POST/GET /v1/friends),
  protocol-level encrypt/decrypt with HKDF-derived key, 4 tests
- Telegram Bot API compatibility: /bot/register, /bot/:token/getUpdates,
  sendMessage, getMe — TG-style Update objects with proper message mapping
- ETH address resolution: GET /v1/resolve/:address (0x.../alias/@.../fp),
  bidirectional ETH↔fp mapping stored on key registration
- Seed recovery: /seed command in TUI + web client
- URL deep links: /message/@alias, /message/0xABC, /group/#ops
- Group members with online status in GET /groups/:name/members

Tier 2 — UX polish:
- TUI: /friend, /friend <addr>, /unfriend <addr> with presence checking
- Web: friend commands, showGroupMembers() on group join
- Web: ETH address in header, clickable addresses (click→peer or copy)
- Bot: full WireMessage→TG Update mapping (encrypted base64, CallSignal,
  FileHeader, bot_message JSON)

Documentation:
- USAGE.md rewritten: complete user guide with all commands
- SERVER.md rewritten: full admin guide with all 50+ endpoints
- CLIENT.md rewritten: architecture, commands, keyboard, storage
- LLM_HELP.md created: 1083-word token-optimized reference for helper LLM

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

warzone/crates/warzone-server/src/routes/keys.rs

@@ -46,6 +46,8 @@ struct RegisterRequest {
     #[serde(default)]
     device_id: Option<String>,
     bundle: Vec<u8>,
+    #[serde(default)]
+    eth_address: Option<String>,
 }
 
 #[derive(Serialize)]
@@ -68,6 +70,16 @@ async fn register_keys(
     let device_key = format!("device:{}:{}", fp, device_id);
     let _ = state.db.keys.insert(device_key.as_bytes(), req.bundle);
 
+    // Store ETH address mapping if provided
+    if let Some(ref eth) = req.eth_address {
+        let eth_lower = eth.to_lowercase();
+        // eth -> fp
+        let _ = state.db.eth_addresses.insert(eth_lower.as_bytes(), fp.as_bytes());
+        // fp -> eth (reverse lookup)
+        let _ = state.db.eth_addresses.insert(format!("rev:{}", fp).as_bytes(), eth_lower.as_bytes());
+        tracing::info!("ETH address mapped: {} -> {}", eth_lower, fp);
+    }
+
     tracing::info!("Registered bundle for {} (device: {})", fp, device_id);
     Json(RegisterResponse { ok: true })
 }