Fix Issue #137: Preserve PRIMARY KEY constraints in write()

[autoelk]

When using pandas.to_sql(if_exists="replace"), PRIMARY KEY constraints are lost from SQLite tables. This breaks Anki's synchronization mechanism between devices.

Fix

• Reassign id_column to be the PRIMARY KEY using dtype={'id_column': 'INTEGER PRIMARY KEY'} parameter when calling pandas.to_sql() in raw.py
• Added simple regression tests covering both notes and cards tables

Testing

• All existing tests pass
• New regression test test_primary_key_constraint_preserved validates the fix

[semanticdiff-com[bot]]

Review changes with  

Changed Files

File	Status
ankipandas/raw.py	64% smaller
ankipandas/test/test_regression.py	0% smaller

[autoelk]

I want to note that I did not remove the _override_exception check in collection.py so even if this change is merged, the NotImplementedError will still be raised.