Foreign key corruption: `foreign key has entered an invalid state`

It's possible for foreign keys in Dolt to become corrupted through certain schema changes, exact mechanism unclear at this point. The symptom is that a call to `dolt_commit()` fails with a message like this:

```sql
Failed to commit changes.
cause: foreign key `paperinfo02_ibfk_1` has entered an invalid state, table `paperinfo02` is missing the index `pinc2`
```

The workaround is to drop and recreate the foreign key with the same definition.

```sql
alter table paperinfo02 drop constraint `paperinfo02_ibfk_1`;
alter table paperinfo02 add constraint `paperinfo02_ibfk_1` FOREIGN KEY (`id_coderinfo`) REFERENCES `coderinfo02` (`id_coderinfo`);
```

If you encounter this bug and can reproduce it, please comment to let us know.

Start by finding a reproducible schema-change sequence that leaves a foreign key invalid, then follow the dolt_commit() path that reports the missing index. Use the provided paperinfo02/coderinfo02 example and verify that the corruption no longer occurs, with a regression test covering the failing commit.

Written by the indexing model from the issue text.