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_email_live.py

@@ -0,0 +1,29 @@
+import sys
+import os
+import logging
+
+# Add current directory to path
+sys.path.append(os.getcwd())
+
+# Configure logging
+logging.basicConfig(level=logging.DEBUG)
+
+try:
+    from app.lib_email import send_email
+    print("Successfully imported send_email.")
+    
+    print("Running send_email in TEST mode...")
+    result = send_email(
+        from_email="test@example.com",
+        to_email="test@example.com",
+        subject="Test Email",
+        body_html="<p>Test</p>",
+        test=True
+    )
+    
+    print(f"Result: {result}")
+    
+except Exception as e:
+    print(f"Error during email test: {e}")
+    import traceback
+    traceback.print_exc()