feat: add first-class Bun and Deno runtime support

[lazarv]

First-class Bun & Deno runtime support

Until now, @lazarv/react-server has been a Node.js-first framework with experimental adapter-level support for alternative runtimes. This PR promotes Bun and Deno to fully supported, first-class runtimes — from project scaffolding all the way through development, production builds, and deployment.

What changes for users

Zero-config runtime detection — When you run react-server build or react-server start under Bun or Deno, the framework now automatically detects the runtime and applies the correct adapter. No manual adapter: "bun" or adapter: "deno" configuration is needed anymore (though explicit overrides and --no-adapter still work).

Scaffolding just works — create-react-server now detects the runtime you're using at project creation time and automatically configures package.json scripts accordingly:

• Bun projects get bun --bun react-server ... scripts and trustedDependencies
• Deno projects get deno run -A npm:@lazarv/react-server ... scripts and a deno.json with nodeModulesDir: "manual" + byonm
• Node.js projects continue to work exactly as before

Simplified production start — Instead of requiring users to manually run .bun/start.mjs or .deno/start.mjs, the standard react-server start command now handles everything, including import map generation for Deno and proper process spawning for both runtimes.

What changes under the hood

• Runtime-aware module loading — New loader plugins (lib/loader/bun.mjs and lib/loader/deno.mjs) handle the differences in how each runtime resolves @lazarv/react-server/dist/... specifiers, manifest files, and prebuilt configs during production serving.
• Dev server rendering for Deno — Since Deno doesn't support Node.js worker_threads, a new process-based rendering pipeline (render-process.mjs, render-process-channel.mjs, render-process-spawn.mjs) communicates over stdio, replacing the worker thread approach while keeping the same external API.
• Improved sys.mjs process shim — The Deno process polyfill is now more robust (adds on/off/once/stdout/stderr stubs) and no longer overwrites the real process global when Deno's Node compat layer already provides one.

New examples

• examples/bun/ — A complete Bun example with SSR, client-side hydration, and interactive counter
• examples/deno/ — A complete Deno example with the same feature set plus react-server.deno.json configuration

Testing

• Docker-based integration tests for create-react-server covering Node.js, Bun, and Deno — each runtime is tested in an isolated container to verify that scaffolded projects build and start correctly.
• Vitest snapshot tests verifying the generated project structure for each runtime/preset combination.
• New CI workflow (.github/workflows/create-react-server.yml) runs these tests automatically on push and PR.

Documentation

Updated the getting started guide and deployment docs (English and Japanese) to reflect that Deno is now fully supported, remove the "not supported yet" notices, and document automatic adapter detection along with simplified deployment commands.

[github-actions]

✅ Documentation preview deployed to: https://react-server-docs-nfwlm39wz-lazarv-team.vercel.app