feat: allow routes customization

[sjorobekov]

Summary

• Adds an optional routes argument to setupRoutes to customize route setup.
  Enables transforming routes before registration (e.g., OpenAPI integration).
• Added nodekit to setup callback

Changes

setupRoutes() now accepts optional custom routes parameter

Example

const app = new ExpressKit(nodekit, routes, ({routes, setupRoutes, ...}) => {
    setupBaseMiddleware();
    setupLangMiddleware();
    setupParsers();
    
    // Transform routes before setup
    const registeredRoutes = registerRoutes(routes);
    setupRoutes(registeredRoutes);
    
    setupErrorHandlers();
});

[DakEnviy]

question(blocking): You can just pass already transformed routes in the original expresskit constructor, can't you?

[sjorobekov]

After discussions with @DakEnviy, decided to go the other way