feat(client-ky): add ky client example and build configuration
Add example project demonstrating ky client usage:
- Created @example/openapi-ts-ky package with React/Vite setup
- Configured to use @hey-api/client-ky plugin
- Includes generated client code from Swagger Petstore OpenAPI spec
Updated build configuration:
- Added 'client-ky' to tsdown.config.ts plugin list
- Ensures ky bundle files are copied to dist/clients/ky during build
- Enables runtime access to ky client implementation
This example allows typecheck validation in CI and serves as
documentation for ky client integration.