WASM bridge: web client now uses same crypto as CLI (full interop)

warzone-wasm crate:
- Compiles warzone-protocol to WebAssembly via wasm-pack
- Exposes WasmIdentity, WasmSession, decrypt_wire_message to JS
- Same X25519 + ChaCha20-Poly1305 + X3DH + Double Ratchet as CLI
- 344KB WASM binary (optimized with wasm-opt)

WireMessage moved to warzone-protocol:
- Shared type used by CLI client, WASM bridge, and TUI
- Guarantees identical bincode serialization across all clients

Web client rewritten:
- Loads WASM module on startup (/wasm/warzone_wasm.js)
- Identity: WasmIdentity generates same key types as CLI
- Registration: sends bincode PreKeyBundle (same format as CLI)
- Encrypt: WasmSession.encrypt/encrypt_key_exchange
- Decrypt: decrypt_wire_message (handles KeyExchange + Message)
- Sessions persisted in localStorage (base64 ratchet state)
- Groups: per-member WASM encryption (interop with CLI members)

Server routes:
- GET /wasm/warzone_wasm.js — serves WASM JS glue
- GET /wasm/warzone_wasm_bg.wasm — serves WASM binary
- Both embedded at compile time via include_str!/include_bytes!

Web ↔ CLI interop now works:
- Same key exchange (X3DH with X25519)
- Same ratchet (Double Ratchet with ChaCha20-Poly1305)
- Same wire format (bincode WireMessage)
- Web user can message CLI user and vice versa

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

warzone/Cargo.lock

@@ -798,8 +798,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ff2abc00be7fca6ebc474524697ae276ad847ad0a6b3faa4bcb027e9a4614ad0"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -2638,6 +2640,24 @@ dependencies = [
  "warzone-protocol",
 ]
 
+[[package]]
+name = "warzone-wasm"
+version = "0.1.0"
+dependencies = [
+ "base64",
+ "bincode",
+ "getrandom 0.2.17",
+ "hex",
+ "js-sys",
+ "serde",
+ "serde_json",
+ "uuid",
+ "warzone-protocol",
+ "wasm-bindgen",
+ "web-sys",
+ "x25519-dalek",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.1+wasi-snapshot-preview1"