Add encrypted, syncable in-app wallet vaults

[jwahdatehagh]

Summary

Adds a production-oriented encrypted in-app wallet keyring and Wagmi connector.

• encrypts mnemonic payloads with a random AES-256-GCM vault key
• wraps the vault key with an Argon2id passphrase slot and optional WebAuthn PRF passkey slots
• keeps decrypted key material inside a module worker
• supports optimistic-revision stores for cross-device ciphertext sync
• unlocks on demand for message, typed-data, hash, and transaction signing
• locks on connector disconnect and rejects account or chain mismatches
• documents the recovery and browser/XSS trust boundaries

Why

The existing package persisted a plaintext private key in browser storage. This replaces that model with a portable encrypted envelope that an API can store without being able to decrypt or sign with it.

Dependency chain

1. This wallet primitive
2. Layers integration: Integrate encrypted in-app wallet vaults layers#88
3. Networked product flow: https://github.com/networked-art/monorepo/pull/27

Publish this package before releasing the coordinated Layers major.

Validation

• pnpm typecheck
• pnpm test — 4 tests passing
• git diff --check