Types missing in `CmsConfig` for new rich text widget field

[delucis]

Describe the bug
When using decap-cms-app, the configuration types don’t include types for the new richtext widget.

To Reproduce
For example, the following code produces a type error:

import CMS from 'decap-cms-app';

CMS.init({
	config: {
		backend: { name: 'github' },
		collections: [
			{
				name: 'example',
				label: 'Example',
				fields: [{ name: 'body', label: 'Content', widget: 'richtext' }],
				      // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                      // Type '{ name: string; label: string; widget: string; }' is not assignable to type 'CmsField'.
				      //  Type '{ name: string; label: string; widget: string; }' is not assignable to type 'CmsFieldBase & CmsFieldMeta'.
				      //    Type '{ name: string; label: string; widget: string; }' is missing the following properties from type 'CmsFieldMeta': required, index_file, metats(2322)
			},
		],
	},
});

Expected behavior
Setting widget: 'richtext' should not produce a type error

Applicable Versions:

• Decap CMS version: "decap-cms-app": "^3.12.2"
• OS: macOS
• Node.JS version: 24.15