v0.0.2: add version display, detailed self-test with step-by-step decrypt

- Version shown on chat load (v0.0.2)
- Self-test now does step-by-step: X3DH shared secret comparison,
  then manual ratchet init + decrypt (not via decrypt_wire_message)
- Shows: rng output, shared_match, alice/bob shared secrets, decrypt result
- This isolates whether X3DH or ratchet or AEAD fails

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

warzone/crates/warzone-wasm/Cargo.toml

@@ -19,6 +19,7 @@ hex.workspace = true
 bincode.workspace = true
 x25519-dalek.workspace = true
 ed25519-dalek.workspace = true
+rand.workspace = true
 uuid = { version = "1", features = ["v4", "serde", "js"] }
 
 # profile.release is set at workspace root