Refactor event and session column names to camelCase

- Updated test cases to reflect new column names (eve_MAC -> eveMac, eve_DateTime -> eveDateTime, etc.) across various test files.
- Modified SQL table definitions in the database cleanup and migration tests to use camelCase naming conventions.
- Implemented migration tests to ensure legacy column names are correctly renamed to camelCase equivalents.
- Ensured that existing data is preserved during the migration process and that views referencing old column names are dropped before renaming.
- Verified that the migration function is idempotent, allowing for safe re-execution without data loss.

test/backend/test_safe_builder_unit.py

@@ -15,7 +15,7 @@ sys.modules['logger'] = Mock()
 class SafeConditionBuilderForTesting:
     """Minimal SafeConditionBuilder implementation for tests."""
 
-    ALLOWED_COLUMNS = {'devName', 'eve_MAC', 'eve_EventType'}
+    ALLOWED_COLUMNS = {'devName', 'eveMac', 'eveEventType'}
     ALLOWED_OPERATORS = {'=', '!=', '<', '>', '<=', '>=', 'LIKE', 'NOT LIKE'}
     ALLOWED_LOGICAL_OPERATORS = {'AND', 'OR'}