* Fix sqlite3 Connection initialization check
Add proper __init__ validation for sqlite3.Connection to ensure base class
__init__ is called before using connection methods. This fixes the
test_connection_constructor_call_check test case.
Changes:
- Modified Connection.py_new to detect subclassing
- For base Connection class, initialization happens immediately in py_new
- For subclassed Connection, db is initialized as None
- Added __init__ method that performs actual database initialization
- Updated _db_lock error message to match CPython: 'Base Connection.__init__ not called.'
This ensures CPython compatibility where attempting to use a Connection
subclass instance without calling the base __init__ raises ProgrammingError.
* use Initializer trait
2faa05dcfb