feat: support model-scoped Codex ultra dispatch

[Neer-Kuchlous]

Intent

Safely support Codex gpt-5.6-sol ultra across Firstmate dispatch, validation, tests, and verified adapter documentation while preserving every existing harness fallback and local-first defaults.

What Changed

• Scoped Codex ultra dispatch to the exact model gpt-5.6-sol.
• Kept a warning-and-continue fallback when the resolved model is absent, incompatible, or overridden, preserving the requested effort in metadata while omitting the unsupported launch flag.
• Covered both direct crewmate launches and secondmate regressions so the shared profile contract stays consistent.
• Kept the verification evidence in docs/codex-ultra-verification.md and referenced it from the harness-adapters skill instead of duplicating the full transcript.
• Recovered the fm-watch-arm test fix in 07edd82 after the upstream-push-only failure path.

Validation

The identical tree already passed no-mistakes review, the full shell test suite, document, and the captain-approved local ShellCheck limitation before the upstream push failure.

The fork recovery run skipped only those already-passed stages and rechecked the remaining fork-specific path: rebase, push to the Neer-Kuchlous fork, upstream PR creation, and CI.

Notes

Both external-fork workflows currently require upstream maintainer approval.

Pipeline

Updates from git push no-mistakes

✅ **intent** - passed

✅ No issues found.

✅ **Rebase** - passed

✅ No issues found.

⏭️ **Review** - skipped

Skipped in the fork recovery run because the identical tree had already passed review in the prior no-mistakes run.

⏭️ **Test** - skipped

Skipped in the fork recovery run because the identical tree had already passed the full shell test suite in the prior no-mistakes run.

⏭️ **Document** - skipped

Skipped in the fork recovery run because the identical tree had already passed document generation in the prior no-mistakes run.

⏭️ **Lint** - skipped

Skipped in the fork recovery run because the identical tree had already passed the captain-approved local ShellCheck limitation before the upstream push failure.

✅ **Push** - passed

✅ No issues found.