fix: correct test suite failures for async price download

Fixed two test issues:
1. test_config_override.py: Updated hardcoded worktree path from config-override-system to async-price-download
2. test_dev_database.py: Added thread-local connection cleanup to prevent SQLite file locking issues

All tests now pass:
- Unit tests: 200 tests
- Integration tests: 47 tests (46 passed, 1 skipped)
- E2E tests: 3 tests
- Total: 250 tests collected

tests/unit/test_dev_database.py

@@ -42,6 +42,11 @@ def test_initialize_dev_database_creates_fresh_db(tmp_path, clean_env):
     assert cursor.fetchone()[0] == 1
     conn.close()
 
+    # Clear thread-local connections before reinitializing
+    import threading
+    if hasattr(threading.current_thread(), '_db_connections'):
+        delattr(threading.current_thread(), '_db_connections')
+
     # Initialize dev database (should reset)
     initialize_dev_database(db_path)