v0.0.22: version bump, ETH identity in web client, version bump rule

Version:
- Workspace + protocol: 0.0.21 → 0.0.22
- Web client VERSION: 0.0.17 → 0.0.22
- Service worker cache: wz-v2 → wz-v3

ETH identity:
- Added WasmIdentity::eth_address() export (derives from seed via secp256k1)
- Web client sends eth_address during key registration
- Identity display shows ETH address first, then fingerprint
- No more server-side resolve needed — computed client-side

CLAUDE.md:
- Added MANDATORY version bump rule (4 places to update)
- Must bump on every functional change, never skip SW cache

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

warzone/crates/warzone-wasm/src/lib.rs

@@ -52,6 +52,12 @@ impl WasmIdentity {
         Seed::from_bytes(self.seed_bytes).to_mnemonic()
     }
 
+    /// Get the Ethereum address derived from this seed.
+    pub fn eth_address(&self) -> String {
+        let eth = warzone_protocol::ethereum::derive_eth_identity(&self.seed_bytes);
+        eth.address.to_checksum()
+    }
+
     /// Get the pre-key bundle as bincode bytes (for server registration).
     /// The bundle is generated once and cached. The SPK secret is stored internally.
     pub fn bundle_bytes(&mut self) -> Result<Vec<u8>, JsValue> {