Address review feedback: Improve UTC compatibility implementation

- Enhance datetime_compat.py documentation
- Add edge case tests for UTC timezone handling
- Update mock patching in tests
- Fix utcnow usage in sqlite.py

Co-Authored-By: Joe Moura <joao@crewai.com>

tests/utilities/test_datetime_compat.py

@@ -1,5 +1,5 @@
 """Test datetime compatibility module."""
-from datetime import timezone
+from datetime import datetime, timedelta, timezone
 
 from crewai.utilities.datetime_compat import UTC
 
@@ -9,6 +9,27 @@ def test_utc_timezone_compatibility():
     assert UTC == timezone.utc
     assert UTC.tzname(None) == "UTC"
     # Verify it works with datetime.now()
-    from datetime import datetime
     dt = datetime.now(UTC)
     assert dt.tzinfo == timezone.utc
+
+
+def test_utc_timezone_edge_cases():
+    """Test UTC timezone handling in edge cases."""
+    # Test with leap year
+    leap_date = datetime(2024, 2, 29, tzinfo=UTC)
+    assert leap_date.tzinfo == timezone.utc
+    
+    # Test DST transition dates
+    dst_date = datetime(2024, 3, 10, 2, 0, tzinfo=UTC)  # US DST start
+    assert dst_date.tzinfo == timezone.utc
+    
+    # Test with minimum/maximum dates
+    min_date = datetime.min.replace(tzinfo=UTC)
+    max_date = datetime.max.replace(tzinfo=UTC)
+    assert min_date.tzinfo == timezone.utc
+    assert max_date.tzinfo == timezone.utc
+    
+    # Test timezone offset calculations
+    dt = datetime(2024, 1, 1, tzinfo=UTC)
+    offset = dt.utcoffset()
+    assert offset == timedelta(0)  # UTC should always have zero offset