[Bug]: CHECK constraints are parsed but not enforced

### Is there an existing issue for the same bug?

- [X] I have checked the existing issues.

### Branch Name

v4.0.0-rc3

### Commit ID

8.0.30-MatrixOne-v4.0.0-rc3

### Other Environment Information

- Hardware parameters: N/A
- OS type: N/A
- Others: Reproduced via cross-language ORM compatibility testing (PHP / Python / Java / Node.js) over the MySQL 8.0.30 wire protocol. The minimal repro below uses raw SQL so it is driver-independent.

### Actual Behavior

`CHECK` is accepted at DDL time but never enforced on writes, so a row that violates it is accepted.

```sql
INSERT INTO t VALUES (-5); -- MatrixOne: accepted
```

### Expected Behavior

The violating row is rejected:

```sql
INSERT INTO t VALUES (-5); -- MySQL 8.0.16+: rejected (ERROR 3819 Check constraint violated)
```

### Steps to Reproduce

```sql
CREATE TABLE t (age INT CHECK (age >= 0));
INSERT INTO t VALUES (-5); -- MySQL 8.0.16+: rejected MatrixOne: accepted
SELECT * FROM t; -- MatrixOne: returns the -5 row
```

### Additional information

Application invariants relying on `CHECK` become silent no-ops.

**Background:** dengn/php-tester#1.