feat(solana): authenticate Relay LUT routes without blind signing

[BitHighlander]

Outcome

KeepKey 7.16 can authenticate reviewed Relay Solana deposit routes, including versioned transactions whose security-critical accounts come from address lookup tables. Vault defaults the certified path on for 7.16+, refuses partial or malformed proof material, and falls back to explicit Advanced Mode only when certification is genuinely unavailable.

Stack

• Firmware alpha: aee78b1ff4addba8810935f290f7e15e13c73dd9
• hdwallet develop: c789d6ae78553034ec242f6c742ee7ed2cdf0d14
• device-protocol: f54f0a7dabb2d38c6f423bf6b6a68e8f979b1b53
• production signer: https://keepkey-clearsign.bithighlander.workers.dev
• signer fingerprint: a9531b9d

Security behavior

• Firmware verifies the scoped certificate, schema signature, transaction hash, canonical LUT account order, program, instruction bytes, and displayed amount.
• Unknown, partial, mixed, tampered, or stale proof material fails closed.
• Solana is production-ready; Ethereum remains visibly provisioning until its separate scoped certificate exists.
• The service stores no application transactions and never receives seed, PIN, passphrase, private key, or device signature.

Evidence

• Vault certified signer/schema/LUT/policy/registry and real Relay fixtures: 37 passed.
• Firmware local native suites: 538 firmware, 21 board/storage, 18 crypto, 6 constant-time passed.
• Firmware PR #607 complete hosted matrix and aggregate CI gate passed.
• Python harness PR fix: CSV report exports were dead clicks #61 complete GitHub and CircleCI emulator suites passed.
• Production Worker readiness and exact/tamper paths verified.
• Backend bundle, Vite production build, external dependency collection, and Electrobun desktop packaging passed.

The macOS 26.4.1 host iconutil tool rejects even iconsets extracted from Apple system icons. Local packaging used a checksum-pinned previously generated AppIcon from the same checked-in Vault artwork; no workaround is committed and normal release builders remain unchanged.

[BitHighlander]

Live alpha acceptance passed on 2026-08-26. Vault head e7bdb62 used firmware alpha aee78b1ff4addba8810935f290f7e15e13c73dd9 and production ClearSign signer a9531b9d. A real Relay SOL→ETH transaction received a 101-byte certified schema and 139-byte Solana-scoped certificate, reached six readable emulator confirmation pages with Advanced Mode off, signed, and broadcast successfully as 5w3U3cWs5hApCe59byfp1bRD9mUXEwKvtTmZzVjfubkWU4fz2RPnEdtesprVvS4Szd6J7NVz2L5TQbveBZa6jGsY. The initial rejection was traced to Vault make build-emulator configuring KK_CLEARSIGN_ALPHA_ROOT=OFF; e7bdb62 aligns the local developer emulator with the CI emulator and adds a fail-fast CMakeCache assertion.