feat(examples): Add official integration samples for popular frameworks

[Dahkenangnon]

Problem

Provide complete, runnable integration examples demonstrating how to use @oidfed with popular JavaScript frameworks and runtimes.

Proposed shape

Proposed Examples Structure

examples/
  next-js/
    app-router/       # Next.js App Router
    pages-router/     # Next.js Pages Router
  remix/
  sveltekit/
  express/
  fastify/
  hono/
  nestjs/
  runtimes/
    cloudflare-workers/
    vercel-edge/
    bun/
    deno/
  identity/
    auth-js/          # Auth.js/NextAuth integration
    passport/

Each Example Should Include

1. Trust Anchor Setup

   • Entity Configuration endpoint
   • Subordinate management
   • Configuration file

2. Leaf Entity Setup

   • Entity Configuration serving
   • Trust chain resolution
   • Authority hints configuration

3. OIDC Integration (where applicable)

   • Automatic registration flow
   • Explicit registration flow
   • Request Object handling

4. Documentation

   • README.md with:
     • Overview
     • Prerequisites
     • Installation steps
     • Running locally
     • Deployment notes
   • Inline code comments

5. Testing

   • Smoke test or basic test suite
   • Instructions for running tests

Implementation Notes

• Each example should be self-contained with its own package.json
• Use workspace:* protocol for referencing @oidfed/* packages
• Include .env.example for configuration
• Provide both HTTP and HTTPS setups
• Document production considerations

Good First Issue

Community contributions welcome! Each framework can be tackled independently.

Alternatives considered (optional)

No response