fix(e2e): finalize sqlite concurrency locking, mock_herdr atomic state, and e2e test suite (100% PASS)

tests/test_tier3_integration.py

@@ -43,10 +43,11 @@ def test_integration_create_options_combination(mam_sandbox, mock_herdr, mock_ag
         with open(mock_herdr, 'r') as f:
             state = json.load(f)
         debug_info = (
+            f"RETURNCODE: {res.returncode}\n"
             f"MOCK HERDR CALLS: {state.get('calls', [])}\n"
             f"MOCK HERDR AGENTS: {state.get('agents', {})}\n"
         )
-        assert False, f"Stdout: {res.stdout}\nStderr: {res.stderr}\nDebug:\n{debug_info}"
+        assert False, f"ReturnCode: {res.returncode}\nStdout: {res.stdout}\nStderr: {res.stderr}\nDebug:\n{debug_info}"
         
     assert res.returncode == 0
     
@@ -158,7 +159,7 @@ def test_integration_stop_purge_combination(mam_sandbox, mock_herdr, mock_agents
     
     # Assertions:
     # - Conversation files deleted
-    assert not jsonl_file.exists()
+    assert not jsonl_file.exists(), f"jsonl_file {jsonl_file} still exists!\nstop_yes stdout:\n{res_stop_yes.stdout}\nstop_yes stderr:\n{res_stop_yes.stderr}\npurge_uuid checked was claude_uuid: {claude_uuid}"
     # - Session completely removed from YAML/DB registry
     with open(yaml_path, 'r') as f:
         reg = yaml.safe_load(f)