fix(3569): surface phase_status from init.plan-phase + gate /gsd:plan-phase on closed phases

Adds a new `phase_status` field to the `init.plan-phase` SDK + CJS query
output and a §1.5 "Closed-Phase Gate" in workflows/plan-phase.md that
short-circuits on closed phases instead of silently replanning over
shipped code.

## What was broken

`gsd-sdk query init.plan-phase <N>` returned the same "ready to plan"
payload for a closed phase (REQUIREMENTS Met, VERIFICATION.md status:
passed, ROADMAP flipped) as for an open one. No field signaled closure,
so `/gsd:plan-phase --reviews` happily replanned over closed phases —
risking documentation drift on already-shipped code.

## Fix

- Export `determinePhaseStatus` from `commands.cjs` (already present, was
  module-private).
- Both `cmdInitPlanPhase` (CJS) and `initPlanPhase` (TS SDK) now compute
  `phase_status` from plan/summary counts + VERIFICATION.md status using
  the existing `determinePhaseStatus` helper — the project-wide phase
  lifecycle vocabulary (Pending | Planned | In Progress | Executed |
  Complete | Needs Review). No directory yet → Pending.
- Workflow `plan-phase.md` adds §1.5 "Closed-Phase Gate":
  - `phase_status == "Complete"` with `--reviews` → hard-stop, no
    override (replanning a closed phase via review feedback is never
    legitimate; concerns belong in a follow-up phase or new issue).
  - `phase_status == "Complete"` without `--force` → exit with a clear
    notice pointing at VERIFICATION.md.
  - `phase_status == "Complete"` with `--force` → continue with a
    transcript banner so the deliberate replan is visible.

`Executed` and `Needs Review` are intentionally not gated — those mean
planning finished but verification did not pass, and replanning is the
correct next step.

## Tests

- SDK: 4 new `phase_status` cases in init.test.ts covering Pending /
  Planned / Executed / Complete transitions.
- Existing init.plan-phase golden parity test continues to pass (the
  `researcher_model: '' vs sonnet` drift in that test predates this
  change and is unrelated).
- Full Mac+Docker suite: 9323 / 9323 passed (Mac), 9318 / 9323 passed
  (Docker, 5 skipped).

Fixes #3569

sdk/src/query/init.ts

@@ -28,6 +28,7 @@ import { resolveModel, MODEL_PROFILES } from './config-query.js';
 import { maskIfSecret } from './secrets.js';
 import { findPhase } from './phase.js';
 import { roadmapGetPhase, getMilestoneInfo, extractCurrentMilestone, extractPhasesFromSection } from './roadmap.js';
+import { determinePhaseStatus } from './progress.js';
 import { planningPaths, normalizePhaseName, toPosixPath, resolveAgentsDir, detectRuntime } from './helpers.js';
 import { generatePhaseSlug, assertSafeProjectCode } from './phase-lifecycle-policy.js';
 import type { QueryHandler } from './utils.js';
@@ -469,6 +470,17 @@ export const initPlanPhase: QueryHandler = async (args, projectDir, workstream)
   const phaseName = (phaseInfo?.phase_name as string) ?? null;
   const phaseDir = (phaseInfo?.directory as string) ?? null;
   const plans = (phaseInfo?.plans || []) as string[];
+  const summaries = (phaseInfo?.summaries || []) as string[];
+
+  // #3569: surface phase lifecycle status so /gsd-plan-phase can short-circuit
+  // on closed (Complete) phases instead of silently replanning over shipped
+  // code. Reuses determinePhaseStatus — the project-wide vocabulary used by
+  // `progress` (Pending | Planned | In Progress | Executed | Complete |
+  // Needs Review). When the phase has no directory on disk yet, treat it as
+  // Pending (it has not been started).
+  const phaseStatus = phaseDir
+    ? await determinePhaseStatus(plans.length, summaries.length, join(projectDir, phaseDir))
+    : 'Pending';
 
   // #3287: compute the canonical directory name with project_code prefix so
   // the first-touch mkdir in /gsd-plan-phase stays consistent with phase.add.
@@ -503,6 +515,7 @@ export const initPlanPhase: QueryHandler = async (args, projectDir, workstream)
     phase_slug: (phaseInfo?.phase_slug as string) ?? null,
     padded_phase: phaseNumber ? normalizePhaseName(phaseNumber) : null,
     phase_req_ids,
+    phase_status: phaseStatus,
     has_research: (phaseInfo?.has_research as boolean) || false,
     has_context: (phaseInfo?.has_context as boolean) || false,
     has_reviews: (phaseInfo?.has_reviews as boolean) || false,