feat: integrate OIDC token exchange in GitHub Action

- Add setupGitHubInstallationToken utility for OIDC token generation
- Implement automatic token exchange with Pullfrog API endpoint
- Add support for multiple authentication methods (input, env, OIDC)
- Create setup utilities for test repository management
- Update action entry point to handle new token flow
- Add environment variable documentation for API key
- Remove large bundled dependencies and optimize build
- Support both development and production token workflows

utils/index.ts

@@ -1,3 +1,5 @@
 export * from "./files";
+export * from "./github";
+export * from "./setup";
 export * from "./subprocess";
 export * from "./table";