feat: enforce status:in_progress when task has calendar date

[bborbe]

Summary

Enforce the calendar-as-commitment invariant: any task with a calendar date (planned_date, defer_date, or due_date) must have status: in_progress (or terminal). Closes silent-miss failure mode where status: next + future date hides tasks from Kanban (filter is status=in_progress&status=completed).

Spec: 017-enforce-status-in-progress-on-calendar-date

Three enforcement points

1. Lint detect + fix (prompt 138) — pkg/ops/lint.go adds IssueTypeStatusDateMismatch; vault-cli task lint --fix promotes next/backlog → in_progress; same detector serves task validate
2. Defer auto-promote (prompt 139) — pkg/ops/defer.go::findAndDeferTask writes status: in_progress in the same atomic file write as defer_date for next/backlog tasks; idempotent on in_progress; terminal statuses (completed/aborted/hold) untouched
3. Task-creator emission (prompt 140) — agents/task-creator.md Step 8 emits status: in_progress when any date field is being written, status: next otherwise; docs/task-writing.md Lifecycle gains a "Calendar-as-commitment rule" subsection; CHANGELOG.md ## Unreleased bullet

Out of scope (intentionally deferred)

• task-auditor agent — semantic/judgment checks only; deterministic field-combo belongs in Go lint
• task set CLI warn-and-offer-promote flag
• One-time vault sweep — separate task once lint rule ships
• Step 13 success-message echo in task-creator — separate follow-up

Test plan

• make precommit green
• vault-cli task lint on a status: next + defer_date fixture reports STATUS_DATE_MISMATCH
• vault-cli task lint --fix promotes status, leaves date byte-identical
• vault-cli task validate <fixture> surfaces the same issue (single source of truth)
• vault-cli task defer on status: next task auto-promotes to in_progress
• vault-cli task defer on status: in_progress task is idempotent (no re-write)
• task-creator agent emits status: in_progress when given date field
• Local `/coding:pr-review` loop converges
• Bot reviewer approves

[ben-s-pull-request-reviewer]

Based on my review of the changed files, here is my assessment:

Summary: The PR implements the calendar-as-commitment rule (spec 017) correctly across three enforcement points: lint detection/fix, defer-time auto-promote, and task-creator agent. The code is well-structured, follows existing patterns, and the test coverage is comprehensive.

Must Fix (Critical): None

Should Fix (Important): None — implementation is sound

Nice to Have (Optional): One minor edge case in lint.go

---

Detailed Findings

1. pkg/ops/lint.go:569-581 — detectStatusDateMismatch regex

Finding: The date value regex [^\s'"]+ doesn't match quoted values containing spaces, e.g., defer_date: "2026-12-01 12:00" (quoted string with a space).

dateRegex := regexp.MustCompile(
    `(?m)^(planned_date|defer_date|due_date):\s*['"]?([^\s'"]+)?['"]?\s*$`,
)

Impact: Low — ISO dates don't contain spaces; quoted datetime strings with spaces are uncommon in this vault's date format conventions.

Verdict: Accept as-is. The pattern matches the project's established date format (ISO 8601 without spaces in quoted values).

---

2. pkg/ops/lint.go:775 — ReplaceAllString usage in fixStatusDateMismatch

Finding: Uses ReplaceAllString rather than replacing only the first occurrence. If the frontmatter contained duplicate status lines (which would also be a DUPLICATE_KEY lint issue), all would be replaced.

newContent := statusRegex.ReplaceAllString(content, "status: in_progress")

Impact: Minimal — YAML frontmatter with duplicate keys is already flagged as DUPLICATE_KEY; the replace-all behavior is correct for the single-status case.

Verdict: Accept as-is.

---

3. pkg/ops/defer.go:147-152 — Auto-promote atomicity

Finding: The concern about atomicity is addressed correctly. The status promotion and defer-date write happen in-memory, then a single WriteTask call persists both atomically:

if status := task.Status(); status == domain.TaskStatusNext ||
    status == domain.TaskStatusBacklog {
    if err := task.SetStatus(domain.TaskStatusInProgress); err != nil {
        return nil, errors.Wrap(ctx, err, "set status to in_progress")
    }
}
// ... later ...
if err := d.taskStorage.WriteTask(ctx, task); err != nil {
    return nil, errors.Wrap(ctx, err, "write task")
}

If SetStatus fails, WriteTask is never called — no partial write occurs.

Verdict: Correctly implemented.

---

4. pkg/ops/lint_test.go — Test isolation

Finding: The new 330-line STATUS_DATE_MISMATCH suite properly isolates each test case. AfterEach cleans up vaultPath, and each subtest writes to a unique filename via writeSDM. No cross-test contamination.

---

5. pkg/ops/defer_test.go — Renamed test behavior

Finding: The test at line 70 ("promotes status from next (todo alias) to in_progress") correctly reflects the new behavior: status: todo (alias for next) is auto-promoted to in_progress on defer. The behavior change is intentional per spec 017.

---

6. agents/task-creator.md:114 — Conditional status emit

Finding: Step 8 correctly implements the spec rule: status: in_progress is emitted when any date field is being written, status: next otherwise. The conditional is clear and well-documented.

---

{
  "verdict": "approve",
  "summary": "The PR implements spec 017 (calendar-as-commitment rule) correctly across lint detection/fix, defer-time auto-promote, and task-creator agent. Code follows existing patterns in the codebase. The atomic write concern in defer.go is resolved — status change and file write happen in one WriteTask call. Test coverage is comprehensive for all three enforcement points.",
  "comments": [],
  "concerns_addressed": [
    "correctness: auto-promote block in findAndDeferTask — SetStatus error handling wraps correctly, WriteTask is called once atomically after all in-memory changes",
    "correctness: detectStatusDateMismatch regex — handles the project's date format conventions (unquoted ISO dates); edge case with quoted values containing spaces is low risk",
    "correctness: fixStatusDateMismatch ReplaceAllString — only matches status:next or status:backlog lines; duplicate status would already be DUPLICATE_KEY",
    "tests: STATUS_DATE_MISMATCH test suite — proper isolation via unique filenames per subtest, AfterEach cleanup",
    "tests: defer_test.go renamed test behavior — status:todo alias correctly auto-promotes to in_progress"
  ]
}