fix: fast node creation, first-run modal, simplified docs

- Skip AI calls when no valid OpenAI key (fixes 9-13s timeout)
- Add first-run modal prompting for API key
- Rewrite README for first-time users
- Add /api/health endpoint
- Remove all Anthropic references (not used in OS)
- Fix bootstrap script (dev:local → dev)
- Fix next.config.js devIndicators warning
- Add Node 18+ version check

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

next.config.js

@@ -6,8 +6,8 @@ const nextConfig = {
       allowedOrigins: ['localhost:3000'],
     },
   },
-  devIndicators: false,
-  
+  // devIndicators removed - use default behavior
+
   typescript: {
     ignoreBuildErrors: false,
   },