Control generation of custom types

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### Is your feature request related to a problem? Please describe.

I use custom types to define a per-resource ID (ash_object_ids). These custom types currently result in `z.any()` in the generated zod schema.

### Describe the solution you'd like

Custom types can determine themselves how they should be generated. Perhaps something like

```
defmodule MyCustomType do
use Ash.Type
# ...
def typescript_type_name, do: "MyCustomType"
def typescript_format_type(formatter), do: ...
end
```

### Describe alternatives you've considered

_No response_

### Additional context

https://github.com/drtheuns/ash_object_ids/blob/main/lib/type.ex#L15

Start by reading the custom type example in the linked ash_object_ids lib/type.ex file and inspect how this project turns custom Ash types into generated Zod schemas. Trace the path that currently emits z.any(); done means a custom type can provide its own TypeScript name and formatting behavior instead of always becoming z.any().

Written by the indexing model from the issue text.