feat(component-meta): expose runtime values of enum members in schema

[valentinpalkovic]

TS enum members currently resolve to their qualified name only ("MyEnum.Small"), because resolveSchema falls through to typeToString. The runtime value is lost, even though the type checker has it at that exact spot (subtype.value on the literal type).

Consumers cannot recover the values without running their own type checker over the user's project. For docs tooling this matters: Storybook, for example, generates a select control from enum schemas, and with only the member names available it either injects the literal string "MyEnum.Small" into the component (wrong value) or has to drop the control entirely (storybookjs/storybook#35565).

This PR adds a literal schema node for enum member types:

// enum MyStringEnum { Small = 'small', ... }  →  prop: MyStringEnum
{
  kind: 'enum',
  type: 'MyStringEnum',
  schema: [
    { kind: 'literal', type: 'MyStringEnum.Small', value: '"small"' },
    { kind: 'literal', type: 'MyStringEnum.Medium', value: '"medium"' },
    { kind: 'literal', type: 'MyStringEnum.Large', value: '"large"' },
  ],
}

• value is printed like literal-union members already are: strings quoted, numbers bare.
• Scoped to TypeFlags.EnumLiteral literal types only: Plain literal unions ('a' | 'b') keep their existing string form, so existing consumers are unaffected there.
• PropertyMetaSchema gains one variant: { kind: 'literal'; type: string; value: string }.
• Tests: string enum added to the reference-type-props fixture with a new assertion; the numeric enum snapshot and the tsc dts snapshot are updated accordingly.