fix(bin): make captain decision lookup archive-aware

[kuan0808]

Intent

Implement the minimal Firstmate-side integration for archive-aware resolved captain-decision lookup using the audited tasks-axi PR 21 pin. Durable decision identity reads must use explicit read-only tasks-axi show --include-archive --full with active-first canonical first-match behavior, while every mutation remains active-only. True absence must require the exact canonical NOT_FOUND envelope and stay distinct from missing or malformed archive-aware tool capability. Preserve active decisions, malformed records, duplicate semantics, privacy-safe output, other backends, and unrelated lifecycle behavior. Add Bash 3.2-compatible focused coverage for active hits, archive fallback, active shadowing, true misses, configured and default archive paths, capability absence, malformed output, archived mutation refusal, and a privacy-safe integration probe of the active local pin. Isolate all real-binary tests from ambient tasks-axi configuration. Keep exact mechanics in the script help/header and tests without changing tasks-axi, pin records, AGENTS.md, or policy unless semantics genuinely require it.

What Changed

• Make durable captain-decision identity reads archive-aware with active-first lookup, strict output validation, and exact canonical NOT_FOUND handling.
• Keep mutations active-only by rejecting archived hold changes while allowing resolved decisions to be verified and retried without archive mutation.
• Add Bash 3.2-compatible regression coverage and documentation for archive fallback, shadowing, true misses, malformed capability output, duplicate fields, and the privacy-safe local integration probe.

Risk Assessment

✅ Low: Captain, the narrow validator fix correctly prevents malformed duplicate-title output from reaching mutation; only its recorded verification output is stale.

Testing

After inspecting the base-to-target delta and confirming Bash 3.2.57/tasks-axi 0.2.3, all focused, lifecycle, cleanup, projection, and brief suites passed; lifecycle and cleanup were rerun to definitive completion after an initial parallel yield, while a synthetic real-CLI transcript demonstrated archive fallback, active shadowing, exact miss handling, mutation refusal, and unchanged persisted files.

Evidence: Archive-aware lookup end-to-end CLI transcript

Archive-aware captain-decision lookup: end-to-end CLI evidence
Synthetic identifiers and content only; ambient tasks-axi HOME/overrides are unset.
bash: GNU bash, version 3.2.57(1)-release (arm64-apple-darwin25)
tasks-axi: 0.2.3

1) Archived record returned by the real active-first lookup:
task:
  id: demo-review-decision-route
  source: archive
  title: Synthetic resolved decision
  state: done
  blocked: no
  blocked_by: none
  held: no
  hold_reason: "-"
  hold_kind: "-"
  hold_until: "-"
  kind: captain
  repo: sample
  priority: "-"
  created: "-"
  closed: 2026-07-23
  deps: none
  links: none
  body: "Resolution recorded by fm-decision-hold.\nDecision digest: synthetic-digest\nRouted identities: synthetic-route\n\nCaptain decision:\nUse the synthetic route.\n\nRouted work:\n- synthetic-route"

2) Firstmate durable verification succeeds from the default Done archive:
verified: demo-review unresolved-decision inventory

3) Attempting to mutate the archived identity is refused:
exit=1
fm-decision-hold: captain decision demo-review-decision-route is archived and cannot be mutated; use a new decision key for a new decision
active backlog unchanged: yes
Done archive unchanged: yes

4) A same-id active record becomes canonical and shadows archive history:
task:
  id: demo-review-decision-route
  source: active
  title: Synthetic active shadow
  state: queued
  blocked: no
  blocked_by: none
  held: no
  hold_reason: "-"
  hold_kind: "-"
  hold_until: "-"
  kind: captain
  repo: sample
  priority: "-"
  created: 2026-07-23
  closed: "-"
  deps: none
  links: none
  body: ""
verification exit=1
fm-decision-hold: captain decision demo-review-decision-route is neither actively held nor durably resolved

5) True absence preserves the exact canonical envelope:
exit=1
error: "Task \"absent-synthetic-decision\" not found in this backlog"
code: NOT_FOUND
help[1]: Run `tasks-axi list` to see existing tasks

RESULT: archive fallback, active-first shadowing, exact miss handling, and active-only mutation behavior all demonstrated.

Dependency

• tasks-axi PR 21 at unchanged audited head a2fff7a94f8bad1269e12c47b9866246d8376317 supplies show --include-archive --full plus active/archive provenance.
• Firstmate refuses durable lookup when that capability is absent or incompatible.
• The current local pin is temporary; an official release should replace it after parity verification.

Pipeline

Updates from git push no-mistakes

✅ **intent** - passed

✅ No issues found.

✅ **Rebase** - passed

✅ No issues found.

⚠️ **Review** - 1 info

• 🚨 bin/fm-decision-hold.sh:149 - Intent requires malformed archive-aware capability to remain distinct from absence. The new exact-one-field check omits title, although command_hold later consumes it. A malformed successful response containing duplicate title: rows can therefore pass validation and trigger tasks-axi hold; add title to the validated fields and cover this case before merging.

🔧 Fix: Reject duplicate titles before captain hold mutation
1 info still open:

• ℹ️ docs/decision-hold-lifecycle.md:79 - This block claims to contain the test's exact summarized output, but the newly added regression prints ok - duplicate title output refuses active hold mutation and that line is missing here. Add it after the malformed-output case so the verification record remains accurate.

✅ **Test** - passed

✅ No issues found.

• git diff --name-status 6db3b09b34dc23787969416bc4dde37adb02ac94 5e941fdbe9c3695ae4b2d984c41e0a94fabc5ccc plus implementation/test/help inspection
• bash --version → GNU Bash 3.2.57; tasks-axi --version → 0.2.3
• bash tests/fm-decision-hold-archive.test.sh
• bash tests/fm-decision-hold-lifecycle.test.sh
• bash tests/fm-teardown.test.sh
• bash tests/fm-fleet-snapshot-view.test.sh
• bash tests/fm-bearings-snapshot.test.sh
• bash tests/fm-brief.test.sh
• Isolated synthetic CLI probe using real tasks-axi: archived lookup and verification, archived mutation refusal with before/after SHA-256 checks, active-first shadowing, and exact canonical NOT_FOUND output
• bash bin/fm-decision-hold.sh --help contract checks
• git status --short --branch

✅ **Document** - passed

✅ No issues found.

✅ **Lint** - passed

✅ No issues found.

✅ **Push** - passed

✅ No issues found.