Feature Request: Bundle PyNaCl (libsodium) as pre-compiled framework for post-quantum secure key generation

Request to bundle PyNaCl (Python binding for libsodium) as a pre-compiled iOS framework in a-Shell, enabling post-quantum secure key/seed generation directly on iPad/iPhone.

**Use Case:** VRIL LABS builds post-quantum cryptographic tools requiring secure key generation on iOS:
- [VRIL-KEM](https://github.com/VRIL-LABS/vril-kem) — post-quantum cryptographic KEM layer
- [Vril.js](https://github.com/VrilLabs/vril-js) — JavaScript SDK for VRIL-KEM integration

PyNaCl wraps libsodium providing: randombytes_buf (CSPRNG), crypto_kx_keypair (DH key exchange), crypto_sign_keypair (Ed25519), crypto_generichash (BLAKE2b).

**Why pip install fails:** iOS kernel-level AMFI enforcement requires (1) frameworks not naked .so files, (2) same Team ID as host app, (3) Apple-trusted certificate chain. ldid -S pseudo-signatures are rejected. Same root cause as #1024 (pycryptodome).

**Precedent:** a-Shell already bundles _cffi_backend as a framework — same approach works for _sodium.

**What we provide:** Cross-compilation scripts at [apple-pynacl](https://github.com/VrilLabs/apple-pynacl), pre-built nacl._sodium.framework (unsigned, ready for AsheKube signing), pure-Python nacl/ package files.

**Broader impact:** Secure key generation, ChaCha20-Poly1305, Ed25519, X25519, BLAKE2b for all a-Shell users.

**Correspondence:** Happy to discuss integration via GitHub Discussions, Telegram, or WhatsApp — avoiding public email for anti-spam reasons.

Related: #1024