test: add regression test for status DB open in cold sessions

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

src/resources/extensions/gsd/tests/status-db-open.test.ts

@@ -0,0 +1,47 @@
+/**
+ * Regression test for #3691 — /gsd status opens DB before deriveState
+ *
+ * In cold sessions the DB was not opened before deriveState, causing
+ * status to fall back to filesystem-only state.  The fix adds an
+ * ensureDbOpen() call before deriveState in handleStatus.
+ *
+ * Also verifies that quick.ts checks getIsolationMode before branching.
+ */
+
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+import { dirname, join } from 'node:path';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+const coreSrc = readFileSync(
+  join(__dirname, '..', 'commands', 'handlers', 'core.ts'),
+  'utf-8',
+);
+const quickSrc = readFileSync(
+  join(__dirname, '..', 'quick.ts'),
+  'utf-8',
+);
+
+describe('status opens DB before deriveState (#3691)', () => {
+  test('handleStatus calls ensureDbOpen before deriveState', () => {
+    const ensureIdx = coreSrc.indexOf('ensureDbOpen');
+    const deriveIdx = coreSrc.indexOf('deriveState(basePath)');
+    assert.ok(ensureIdx > -1, 'ensureDbOpen call should exist in core.ts');
+    assert.ok(deriveIdx > -1, 'deriveState(basePath) call should exist in core.ts');
+    assert.ok(
+      ensureIdx < deriveIdx,
+      'ensureDbOpen must appear before deriveState so DB is ready',
+    );
+  });
+
+  test('quick.ts checks getIsolationMode before branching', () => {
+    assert.match(quickSrc, /getIsolationMode\(\)/,
+      'quick.ts should call getIsolationMode()');
+    assert.match(quickSrc, /getIsolationMode\(\)\s*!==\s*"none"/,
+      'quick.ts should compare isolation mode against "none"');
+  });
+});