feat(rsc): add import.meta.viteRsc.import API

[hi-ogawa]

Summary

Add import.meta.viteRsc.import() - a more ergonomic API for cross-environment module loading.

import.meta.viteRsc.import: <T>(
  specifier: string,
  options: { environment: "ssr" | "rsc" },
) => Promise<T>

Comparison

Before (loadModule):

// vite.config.ts - must configure entry manually
export default {
  environments: {
    ssr: {
      build: {
        rollupOptions: {
          input: { index: './entry.ssr.tsx' }
        }
      }
    }
  }
}

// entry.rsc.tsx
const ssrModule = await import.meta.viteRsc.loadModule<typeof import('./entry.ssr')>(
  'ssr',
  'index'
);

After (import):

// vite.config.ts - no explicit `rollupOptions.input` needed

// entry.rsc.tsx
const ssrModule = await import.meta.viteRsc.import<typeof import('./entry.ssr')>(
  './entry.ssr',
  { environment: 'ssr' }
);

How it works

• Dev: Uses __VITE_ENVIRONMENT_RUNNER_IMPORT__ (same as loadModule)
• Build: Auto-discovers imports, emits entries, generates manifest (__vite_rsc_env_imports_manifest.js)

Side note: Removal of internal no-ssr build path

This PR removes the internal "no-ssr" build path (4-step pipeline) that was automatically triggered when ssr.rollupOptions.input was not configured. This path was incompatible with auto-discovery—the decision to skip ssr build was made before scanning could discover import.meta.viteRsc.import calls targeting ssr.

This is not a breaking change:

• Build output gains a small unused fallback chunk in ssr output when ssr isn't explicitly configured
• Runtime behavior is unchanged
• Users who want a true no-ssr build can use customBuildApp (see examples/no-ssr)

Documentation

• README.md - API documentation with comparison
• types/index.d.ts - TypeScript types with JSDoc

Test plan

• Implement transform plugin
• Test build mode with starter example
• Verify entry auto-discovery works
• Test dev mode

🤖 Generated with Claude Code