Tests: Reorganize test suite into functional subdirectories

- Categorized scripts into tests/unit/, tests/integration/, tests/e2e/, and tests/tools/.
- Adopted consistent naming prefixes (test_unit_*, test_int_*, test_e2e_*, tool_*).
- Renamed conftest_mock.py to mock_config_helper.py for clarity.
- Updated test_int_boot_diagnosis.py with sys.path setup for root-level execution.

tests/integration/test_int_import_verification.py

@@ -0,0 +1,36 @@
+import sys
+import os
+
+# Add current directory to path
+sys.path.append(os.getcwd())
+
+print("Attempting to import app.lib_general_v3...")
+try:
+    import app.lib_general_v3
+    print("Success: app.lib_general_v3")
+except Exception as e:
+    print(f"Failed: app.lib_general_v3 - {e}")
+    import traceback
+    traceback.print_exc()
+
+print("-" * 20)
+
+print("Attempting to import app.routers.api_crud_v3...")
+try:
+    import app.routers.api_crud_v3
+    print("Success: app.routers.api_crud_v3")
+except Exception as e:
+    print(f"Failed: app.routers.api_crud_v3 - {e}")
+    import traceback
+    traceback.print_exc()
+
+print("-" * 20)
+
+print("Attempting to import app.routers.agent_bridge...")
+try:
+    import app.routers.agent_bridge
+    print("Success: app.routers.agent_bridge")
+except Exception as e:
+    print(f"Failed: app.routers.agent_bridge - {e}")
+    import traceback
+    traceback.print_exc()