test: add regression test for dispatcher stuck-planning reconciliation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/resources/extensions/gsd/tests/dispatcher-stuck-planning.test.ts

@@ -0,0 +1,37 @@
+/**
+ * dispatcher-stuck-planning.test.ts — #3656
+ *
+ * Verify that state.ts contains the disk-to-DB task reconciliation logic
+ * that prevents the dispatcher from getting stuck in an infinite planning
+ * loop when the planner writes a PLAN.md but never calls the persistence
+ * tool, leaving the DB with zero task rows.
+ */
+
+import { describe, test } from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const sourceFile = join(__dirname, "..", "state.ts");
+
+describe("dispatcher stuck-planning reconciliation (#3656)", () => {
+  const source = readFileSync(sourceFile, "utf-8");
+
+  test("imports insertTask from gsd-db", () => {
+    assert.match(source, /import\s*\{[^}]*insertTask[^}]*\}\s*from/);
+  });
+
+  test("contains plan-file task reconciliation block", () => {
+    assert.match(source, /tasks\.length\s*===\s*0\s*&&\s*planFile/);
+  });
+
+  test("calls insertTask for each disk plan task", () => {
+    assert.match(source, /insertTask\(\{/);
+  });
+
+  test("references issue #3600 in reconciliation comment", () => {
+    assert.match(source, /#3600/);
+  });
+});