test: update snapshots for allOf additionalProperties false fix
- Update all OpenAPI version snapshots (2.0.x, 3.0.x, 3.1.x) to reflect fix
- Add missing 2.0.x additional-properties-false test snapshots
- Fix enum type generation (union types instead of keyof typeof patterns)
- Fix client error type handling
- Ensure allOf composition generates clean Foo & {} instead of Foo & { [key: string]: never }
- All 233 tests across all versions now passing (25 + 69 + 139)