Support default for enum fields

### Describe the feature you'd like to request

The enum type doesn't currently support defining default value, e.g. this will not work:
```ts
a.enum(["a", "b"]).default("a")
```

### Describe the solution you'd like

Code like above works, just like with other field types.

### Describe alternatives you've considered

Had to use another field type (boolean or integer)

### Additional context

_No response_

### Is this something that you'd be interested in working on?

- [ ] 👋 I may be able to implement this feature request

### Would this feature include a breaking change?

- [ ] ⚠️ This feature might incur a breaking change

Start by locating how enum fields and defaults are handled for other field types in the TypeScript repository. Verify the enum example with a default value and add or update coverage so completion is demonstrated by the example working like other field types.

Written by the indexing model from the issue text.