feat: signal file for decision points — WAITING.json (#1034) (#1133)

When GSD hits a blocking decision point (AskUserQuestion, next action prompt),
external watchers have no way to detect it. Users monitoring multiple auto
sessions must visually check each terminal.

Added:
- state signal-waiting: writes .planning/WAITING.json (or .gsd/WAITING.json)
  with type, question, options, timestamp, and phase info
- state signal-resume: removes WAITING.json when user answers

Signal file format:
  { status, type, question, options[], since, phase }

External tools can watch for this file via fswatch, polling, or inotify.
Complements the existing remote-questions extension (Slack/Discord).

Fixes #1034

get-shit-done/bin/gsd-tools.cjs

@@ -15,6 +15,8 @@
  *   state get [section]                Get STATE.md content or section
  *   state patch --field val ...        Batch update STATE.md fields
  *   state begin-phase --phase N --name S --plans C  Update STATE.md for new phase start
+ *   state signal-waiting --type T --question Q --options "A|B" --phase P  Write WAITING.json signal
+ *   state signal-resume                Remove WAITING.json signal
  *   resolve-model <agent-type>         Get model for agent based on profile
  *   find-phase <phase>                 Find phase directory by number
  *   commit <message> [--files f1 f2]   Commit planning docs
@@ -255,6 +257,21 @@ async function main() {
           plansIdx !== -1 ? parseInt(args[plansIdx + 1], 10) : null,
           raw
         );
+      } else if (subcommand === 'signal-waiting') {
+        const typeIdx = args.indexOf('--type');
+        const qIdx = args.indexOf('--question');
+        const optIdx = args.indexOf('--options');
+        const phaseIdx = args.indexOf('--phase');
+        state.cmdSignalWaiting(
+          cwd,
+          typeIdx !== -1 ? args[typeIdx + 1] : null,
+          qIdx !== -1 ? args[qIdx + 1] : null,
+          optIdx !== -1 ? args[optIdx + 1] : null,
+          phaseIdx !== -1 ? args[phaseIdx + 1] : null,
+          raw
+        );
+      } else if (subcommand === 'signal-resume') {
+        state.cmdSignalResume(cwd, raw);
       } else {
         state.cmdStateLoad(cwd, raw);
       }

get-shit-done/bin/lib/state.cjs

@@ -778,6 +778,53 @@ function cmdStateBeginPhase(cwd, phaseNumber, phaseName, planCount, raw) {
   output({ updated, phase: phaseNumber, phase_name: phaseName || null, plan_count: planCount || null }, raw, updated.length > 0 ? 'true' : 'false');
 }
 
+/**
+ * Write a WAITING.json signal file when GSD hits a decision point.
+ * External watchers (fswatch, polling, orchestrators) can detect this.
+ * File is written to .planning/WAITING.json (or .gsd/WAITING.json if .gsd exists).
+ * Fixes #1034.
+ */
+function cmdSignalWaiting(cwd, type, question, options, phase, raw) {
+  const gsdDir = fs.existsSync(path.join(cwd, '.gsd')) ? path.join(cwd, '.gsd') : path.join(cwd, '.planning');
+  const waitingPath = path.join(gsdDir, 'WAITING.json');
+
+  const signal = {
+    status: 'waiting',
+    type: type || 'decision_point',
+    question: question || null,
+    options: options ? options.split('|').map(o => o.trim()) : [],
+    since: new Date().toISOString(),
+    phase: phase || null,
+  };
+
+  try {
+    fs.mkdirSync(gsdDir, { recursive: true });
+    fs.writeFileSync(waitingPath, JSON.stringify(signal, null, 2), 'utf-8');
+    output({ signaled: true, path: waitingPath }, raw, 'true');
+  } catch (e) {
+    output({ signaled: false, error: e.message }, raw, 'false');
+  }
+}
+
+/**
+ * Remove the WAITING.json signal file when user answers and agent resumes.
+ */
+function cmdSignalResume(cwd, raw) {
+  const paths = [
+    path.join(cwd, '.gsd', 'WAITING.json'),
+    path.join(cwd, '.planning', 'WAITING.json'),
+  ];
+
+  let removed = false;
+  for (const p of paths) {
+    if (fs.existsSync(p)) {
+      try { fs.unlinkSync(p); removed = true; } catch {}
+    }
+  }
+
+  output({ resumed: true, removed }, raw, removed ? 'true' : 'false');
+}
+
 module.exports = {
   stateExtractField,
   stateReplaceField,
@@ -796,4 +843,6 @@ module.exports = {
   cmdStateSnapshot,
   cmdStateJson,
   cmdStateBeginPhase,
+  cmdSignalWaiting,
+  cmdSignalResume,
 };