[DanielNetzer]

Implements issue #396.

Molecule: mol-396-f16ce31e54f6fa699857047e
Formula: forgecell-github-issue
Base: 244247a3728c8fc95e2ed2a79e9189d0f0a1be12
Delivery: c14b412f3eb7d666c04cf04b89bbd1e7e96e9770

Awaiting exact-commit CI and human review. Harness-reported checks are not independent CI evidence. No merge, deployment or issue closure is authorized.

[DanielNetzer]

Review notes (LOW, not blocking):

• All Codex coding runs in a Lab share one harness cache (<lab>/caches/harness), as Give Codex coding runs a writable Lab-owned Go build cache (#43, slice 1) #396 decided. A run in one Molecule can therefore leave build-cache entries another Codex run reuses. The Lab's own checks keep using their separate cache, so verification isn't affected.
• Only the approved-plan coding stage attaches the cache. Analysis, review and learn requests never carry it, and BuildInvocation refuses the key on them.

Protocol 8. Saved bindings that report protocol 7 need a reviewed rebind after upgrading; this goes in the v0.4.5 notes.

Protected regression: TestAdapterInvocationChangesRequireProtocolBump failed by design (the old test has no pin for protocol 8); accepted with --accept-protected-failures. All checks passed.