Refactor src layout and add logging lifecycle + tests

tests/test_logging_decorator.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+import logging
+import unittest
+
+from src.logging_config import debug_log_lifecycle
+
+
+class TestDebugLogLifecycle(unittest.TestCase):
+    def test_logs_function_start_and_end(self) -> None:
+        @debug_log_lifecycle
+        def sample(a: int, b: int) -> int:
+            return a + b
+
+        with self.assertLogs(sample.__module__, level="DEBUG") as captured:
+            result = sample(2, 3)
+
+        self.assertEqual(result, 5)
+        joined = "\n".join(captured.output)
+        self.assertIn("Start TestDebugLogLifecycle.test_logs_function_start_and_end.<locals>.sample", joined)
+        self.assertIn("End TestDebugLogLifecycle.test_logs_function_start_and_end.<locals>.sample", joined)
+
+
+if __name__ == "__main__":
+    unittest.main()