feat: evaluate approved-plan continuity closure

scripts/approved_plan_continuity_gate.mjs

@@ -1,6 +1,8 @@
 #!/usr/bin/env node
 import fs from 'node:fs';
 
+const LEGAL_TERMINAL_STATES = new Set(['waiting_user', 'blocked', 'pending_verification']);
+
 function parseArgs(argv) {
   let inputPath = null;
   let compact = false;
@@ -38,10 +40,12 @@ function readInput(inputPath) {
 
   try {
     const raw = fs.readFileSync(inputPath, 'utf8');
+    const parsed = JSON.parse(raw);
     return {
       ok: true,
       bytes: Buffer.byteLength(raw, 'utf8'),
       preview: raw.slice(0, 0),
+      parsed,
     };
   } catch (error) {
     return {
@@ -51,17 +55,54 @@ function readInput(inputPath) {
   }
 }
 
+function evaluateContinuity(payload) {
+  const taskComplete = payload?.taskState === 'complete';
+  const nextActionKnown = payload?.nextDerivedAction != null;
+  const hasDispatchReceipt = payload?.dispatchReceipt != null;
+  const closureState = payload?.replyClosureState ?? null;
+  const isLegalTerminalState = LEGAL_TERMINAL_STATES.has(closureState);
+
+  if (taskComplete && nextActionKnown && !hasDispatchReceipt && !isLegalTerminalState) {
+    return {
+      ok: false,
+      status: 'continuity_failure',
+      verdict: 'continuity_failure',
+      reason: 'missing_dispatch_receipt',
+    };
+  }
+
+  return {
+    ok: true,
+    status: 'pass',
+    verdict: 'pass',
+  };
+}
+
 const { inputPath, compact } = parseArgs(process.argv.slice(2));
 const input = readInput(inputPath);
+const evaluation = input.ok ? evaluateContinuity(input.parsed) : {
+  ok: false,
+  status: 'input_error',
+  verdict: 'input_error',
+};
 
 const response = {
-  ok: true,
-  status: 'placeholder',
+  ...evaluation,
   gate: 'approved_plan_continuity',
   compact,
   inputPath,
-  input,
-  verdict: 'not_implemented',
+  input: {
+    ok: input.ok,
+    ...(input.ok
+      ? {
+          bytes: input.bytes,
+          preview: input.preview,
+        }
+      : {
+          error: input.error,
+        }),
+  },
 };
 
-process.stdout.write(`${JSON.stringify(response)}\n`);
+process.stdout.write(`${JSON.stringify(response)}
+`);