chore(hardening): add debt inventory and async io kickoff

tests/unit/jsonl-parser.test.ts

@@ -2,7 +2,7 @@
  * Unit tests for JSONL Parser
  */
 
-import { describe, expect, test, beforeEach, afterEach } from 'bun:test';
+import { describe, expect, test, beforeEach, afterEach, spyOn } from 'bun:test';
 import * as fs from 'fs';
 import * as path from 'path';
 import * as os from 'os';
@@ -254,6 +254,19 @@ describe('parseProjectDirectory', () => {
     const entries = await parseProjectDirectory('/nonexistent/dir');
     expect(entries.length).toBe(0);
   });
+
+  test('returns empty array when directory read fails', async () => {
+    const existsSyncSpy = spyOn(fs, 'existsSync').mockReturnValue(true);
+    const readdirSpy = spyOn(fs.promises, 'readdir').mockRejectedValue(new Error('EACCES'));
+
+    try {
+      const entries = await parseProjectDirectory('/protected/dir');
+      expect(entries).toEqual([]);
+    } finally {
+      existsSyncSpy.mockRestore();
+      readdirSpy.mockRestore();
+    }
+  });
 });
 
 describe('findProjectDirectories', () => {