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Add the device-local wallet onboarding to the SPA. The user's identity is derived deterministically from a 12-word BIP39 mnemonic and lives on the device; the browser never signs, never talks NATS, and never sends the seed to the server. Wallet layer (web/src/wallet/): - derive.ts: deterministic identity from a mnemonic. seed = BIP39 seed, then HKDF-SHA256 domain-separated into an Ed25519 signing key (info "unibus-sign-v1") and an X25519 key-exchange key (info "unibus-kex-v1"). The same mnemonic always yields the same sign_pub, which is what makes recovery possible without admin intervention. The four halves match cs.Identity on the Go side exactly. - bip39.ts: thin wrappers over @scure/bip39 (generate, validate, normalize) so the checksum logic stays in the audited library. - crypto.ts: at-rest encryption of the private key with WebCrypto only (PBKDF2-SHA256 210k iters -> AES-256-GCM). The password never leaves the device and only protects the local key copy. - store.ts: IndexedDB persistence of the encrypted identity (private key encrypted; public halves + handle in the clear for display). - account.ts: saveAndOpen / unlockAndOpen / localIdentity compose the primitives with the gateway session API. Screens: - Welcome: choose invite link or recover-with-seed on an empty device. - Join: generate seed, show it once behind an acknowledge gate, confirm 3 random words, set a local password, register the PUBLIC key with the bus via the invite token, then open the session. - Recover: paste the 12 words, validate, show the reconstructed sign_pub, set a new local password, open the session. No register (the identity is already in the allowlist). - WalletLogin: unlock the device's stored identity with the password. - AuthShell: shared card/header for all pre-chat screens. - App.tsx: route between join / welcome / login / recover / chat based on the invite link, a live gateway session, and any stored identity. api.ts/types.ts: add register() and session() against the gateway contract; vite dev server on :5183. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>