feat(abi-verify): structural ABI gate — Idris2 manifest ↔ Zig FFI dif…

[hyperpolymath]

…f (standards#92 Phase 1)

Adds iseriser abi-verify, a structural CI gate that diffs an Idris2-derived ABI manifest against a cartridge's Zig FFI source. Replaces today's test-only cross-check (ssg-mcp / k9iser-mcp cartridges under boj-server) with a CI-grade gate that catches:

• enum encoding drift (variant integer value mismatches);
• transition-allowed-but-rejected (manifest allows what Zig rejects);
• transition-forbidden-but-accepted (manifest forbids what Zig accepts — the safety-critical class, e.g. ContentLoaded → Previewing for SSG or Generated → Applied for K9);
• transition-accepted-but-undeclared (Zig accept-by-omission);
• transition-table-uses-else (refuses to certify non-exhaustive switches).

Includes hand-authored reference manifests for ssg-mcp (SsgState×11, SsgEngine) and k9iser-mcp (K9State×10, K9Format), both verified clean against the live Zig FFI on boj-server main. Phase 1b will emit the manifests from the Idris2 build; this commit deliberately stops at the verification-harness boundary per the #92 design spec.

Exit code 0 = clean, 2 = drift. JSON output available via --json for CI ingestion.

33 lib tests + 9 integration tests green. New code is clippy-clean (pre- existing baseline warnings on src/scan/mod.rs left as-is).

Refs hyperpolymath/standards#92
Refs hyperpolymath/standards#89

Summary

Changes

RSR Quality Checklist

Required

• Tests pass (just test or equivalent)
• Code is formatted (just fmt or equivalent)
• Linter is clean (no new warnings or errors)
• No banned language patterns (no TypeScript, no npm/bun, no Go/Python)
• No unsafe blocks without // SAFETY: comments
• No banned functions (believe_me, unsafeCoerce, Obj.magic, Admitted, sorry)
• SPDX license headers present on all new/modified source files
• No secrets, credentials, or .env files included

As Applicable

• .machine_readable/STATE.a2ml updated (if project state changed)
• .machine_readable/ECOSYSTEM.a2ml updated (if integrations changed)
• .machine_readable/META.a2ml updated (if architectural decisions changed)
• Documentation updated for user-facing changes
• TOPOLOGY.md updated (if architecture changed)
• CHANGELOG or release notes updated
• New dependencies reviewed for license compatibility (PMPL-1.0-or-later / MPL-2.0)
• ABI/FFI changes validated (src/interface/abi/ and src/interface/ffi/ consistent)

Testing

Screenshots

[hyperpolymath]

Closing as superseded. Branch tip (feat(abi-verify): structural ABI gate — Idris2 manifest ↔ Zig FFI diff (standards#92 Phase 1)) was already merged via #13. Re-diff vs current main shows merging this branch would delete ~2609 lines of subsequently-merged work — net regression.