feat(tbor): implement ShaDigest

[vsonims]

Summary

Adds the TBOR ShaDigest command (opcode 0x1B): within an open session, compute a SHA-256 / 384 / 512 digest of a host-supplied message and return it. A pure hashing utility — no key, no scope, no partition state — the TBOR analogue of MBOR ShaDigest.

Opcode	Command	Session
0x1B	ShaDigest	InSession

Design

• Reserve-then-fill: the response frame is encoded with the digest slot reserved, then the PAL hashes straight into it — no intermediate buffer, no copy.
• Natural big-endian digest output (standard SHA byte order).
• Reuses the shared HashAlgo enum from key_props (SHA-256/384/512).
• In-session: session_id cross-checked by the dispatcher, default-PSK gate applies (like the other TBOR crypto commands), but with no masked keys.

Changes

• Handler fw/core/lib/src/ddi/tbor/sha_digest.rs; dispatch + 3 classifiers in mod.rs; op.rs from_tbor_opcode (InSession).
• Wire schemas (fw + host mirror) + lib.rs registration.
• Emu tests: device digests verified byte-for-byte against host-computed SHA (azihsm_crypto) for all three algorithms over short / empty / long messages, plus an unknown-mode reject.
• Docs: sha_digest.md + README row.

Testing

• cargo check fw core (host + Uno no_std) ✅
• clippy (fw + host) ✅ · nightly fmt ✅ · copyright ✅
• Full TBOR emu suite: 119 passed.

Notes

• Based on feat(tbor): implement RSA-AES key unwrap (GetUnwrappingKey + UnwrapKey) #583 (tbor/unwrap-key) for the shared HashAlgo enum. Uses opcode 0x1B to avoid collision with the sibling AES / ECC / RSA crypto branches (0x15..0x1A).
• Fills one of the identified MBOR→TBOR command gaps; HkdfDerive / KbkdfCounterHmacDerive / cert-chain commands remain.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com