experiment: construct TRUST-001 stock OpenCode candidate

[bateau84]

Status

Authorization A is granted for bounded prototype construction and the named provider-free preflights only.

This PR is stacked on PR #43's reviewed Gate-1 branch and therefore contains only post-Gate-1 authorization/construction changes.

Hard constraints

• OpenCode v2.0.23 is stock and immutable.
• No OpenCode patch, fork, custom binary, or upstream PR.
• Loom production semantics remain unchanged.
• Candidate implementation belongs only to opencode-eval-runner.
• No model/provider inference is authorized.
• No merge/default-pin/release/production adoption is authorized.

Current checkpoint

• Gate-1 baseline: fdbc3c9b1c5314f588ffb3cfd34bf0a19502c2aa
• Authorization A: docs/experiments/trust-001/checkpoints/AUTHORIZATION-A.md
• Gate 2: NOT RUN
• Gate 2C: NOT RUN
• Authorization B: NOT GRANTED

Initial construction order

1. stock OpenCode v2.0.23 provenance;
2. typed capability/evidence protocol primitives;
3. channel admission and generation lifecycle;
4. plugin-source closure;
5. synthetic remote bridge/isolated peer;
6. provider-free preflights named in Authorization A.

Code Mode finality, dynamic transform reload parity, root admission, event drain/seal, cancellation side-effect fidelity and effective OS authority remain UNPROVEN until the later gates.