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

get-shit-done/workflows/plan-phase.md

@@ -45,7 +45,7 @@ When `TDD_MODE` is `true`, the planner agent is instructed to apply `type: tdd`
 
 When `CONTEXT_WINDOW >= 500000`, the planner prompt includes the 3 most recent prior phase CONTEXT.md and SUMMARY.md files PLUS any phases explicitly listed in the current phase's `Depends on:` field in ROADMAP.md. Explicit dependencies always load regardless of recency (e.g., Phase 7 declaring `Depends on: Phase 2` always sees Phase 2's context). Bounded recency keeps the planner's context budget focused on recent work.
 
-Parse JSON for: `researcher_model`, `planner_model`, `checker_model`, `research_enabled`, `plan_checker_enabled`, `nyquist_validation_enabled`, `commit_docs`, `text_mode`, `phase_found`, `phase_dir`, `phase_number`, `phase_name`, `phase_slug`, `padded_phase`, `has_research`, `has_context`, `has_reviews`, `has_plans`, `plan_count`, `planning_exists`, `roadmap_exists`, `phase_req_ids`, `response_language`.
+Parse JSON for: `researcher_model`, `planner_model`, `checker_model`, `research_enabled`, `plan_checker_enabled`, `nyquist_validation_enabled`, `commit_docs`, `text_mode`, `phase_found`, `phase_dir`, `phase_number`, `phase_name`, `phase_slug`, `padded_phase`, `has_research`, `has_context`, `has_reviews`, `has_plans`, `plan_count`, `phase_status` (#3569), `planning_exists`, `roadmap_exists`, `phase_req_ids`, `response_language`.
 
 **If `response_language` is set:** Include `response_language: {value}` in all spawned subagent prompts so any user-facing output stays in the configured language.
 
@@ -53,9 +53,52 @@ Parse JSON for: `researcher_model`, `planner_model`, `checker_model`, `research_
 
 **If `planning_exists` is false:** Error — run `/gsd:new-project` first.
 
+## 1.5. Closed-Phase Gate (#3569)
+
+The init JSON includes `phase_status` — one of `Pending | Planned | In Progress | Executed | Complete | Needs Review`. `Complete` means the phase has all summaries AND a `VERIFICATION.md` with `status: passed`. Replanning a closed phase silently rewrites plan docs that no longer match the shipped code, so the workflow must hard-stop here unless the operator explicitly overrides.
+
+Parse `phase_status` from the init JSON, then:
+
+```bash
+FORCE_REPLAN=false
+if [[ "$ARGUMENTS" =~ (^|[[:space:]])--force([[:space:]]|$) ]]; then
+  FORCE_REPLAN=true
+fi
+
+if [ "${phase_status}" = "Complete" ]; then
+  if [[ "$ARGUMENTS" =~ (^|[[:space:]])--reviews([[:space:]]|$) ]]; then
+    # --reviews on a closed phase is never legitimate — concerns belong in a
+    # new phase or issue against the closed phase's commits.
+    cat <<EOF >&2
+Phase ${phase_number} (${phase_name}) is already CLOSED (VERIFICATION status: passed).
+/gsd:plan-phase --reviews cannot replan a closed phase. If the review surfaced
+real concerns, open a follow-up phase or file an issue against the closed
+phase's commits. There is no --force override for --reviews on a closed phase.
+EOF
+    exit 1
+  fi
+  if [ "$FORCE_REPLAN" != "true" ]; then
+    cat <<EOF >&2
+Phase ${phase_number} (${phase_name}) is already CLOSED (VERIFICATION status: passed).
+Replanning a closed phase will overwrite plan docs that no longer match the
+shipped code. If you intentionally want to replan over closed work, re-run
+with: /gsd:plan-phase ${phase_number} --force
+
+Otherwise, to view what shipped, see: ${verification_path}
+EOF
+    exit 1
+  fi
+  # FORCE_REPLAN=true: continue, but emit a banner so the operator sees the
+  # decision in the transcript and in any committed plan docs.
+  echo "WARNING: Replanning CLOSED phase ${phase_number} under --force. Verify the closeout was wrong before committing new plan docs." >&2
+fi
+```
+
+The gate fires only on `Complete`. `Executed` and `Needs Review` are not gated — those states mean planning was finished but verification did not pass, and replanning is a legitimate next step.
+
 ## 2. Parse and Normalize Arguments
 
-Extract from $ARGUMENTS: phase number (integer or decimal like `2.1`), flags (`--research`, `--skip-research`, `--research-phase <N>`, `--gaps`, `--skip-verify`, `--skip-ui`, `--prd <filepath>`, `--ingest <path-or-glob>`, `--ingest-format <auto|nygard|madr|narrative>`, `--reviews`, `--text`, `--bounce`, `--skip-bounce`, `--chunked`, `--mvp`).
+Extract from $ARGUMENTS: phase number (integer or decimal like `2.1`), flags (`--research`, `--skip-research`, `--research-phase <N>`, `--gaps`, `--skip-verify`, `--skip-ui`, `--prd <filepath>`, `--ingest <path-or-glob>`, `--ingest-format <auto|nygard|madr|narrative>`, `--reviews`, `--text`, `--bounce`, `--skip-bounce`, `--chunked`, `--mvp`, `--force` (override closed-phase gate, see §1.5)).
 
 **`--research-phase <N>` — research-only mode (#3042 + #3044).** When this flag is present, parse `<N>` as the phase number (overrides any positional phase argument), set `RESEARCH_ONLY=true`, and treat the rest of this workflow as a research-dispatch only — the planner spawn (step 8), plan-checker, verification, gaps, bounce, and post-planning-gaps blocks all skip on `RESEARCH_ONLY`. Use this for cross-phase research, doc review before committing to a planning approach, and correction-without-replanning loops. Replaces the deleted `/gsd-research-phase` command.