feat: integrate WebAssembly for zero-latency, offline-first color operations

Replaced REST API dependency with @valknarthing/pastel-wasm (130KB) for
complete browser-based color operations. The application is now fully
static (2.2MB total) with zero network latency and offline support.

**Key Changes:**

1. **WASM Integration:**
   - Added @valknarthing/pastel-wasm dependency (0.1.0)
   - Created lib/api/wasm-client.ts wrapper matching API interface
   - Updated lib/api/client.ts to use WASM client by default
   - All 18 color operations now run locally in browser

2. **Static Export Configuration:**
   - Changed next.config.ts output from 'standalone' to 'export'
   - Disabled image optimization for static export
   - Removed API proxy route (app/api/pastel/[...path]/route.ts)
   - Updated package.json scripts (removed dev:api, added serve)

3. **Docker Optimization:**
   - Migrated from Node.js standalone to nginx-alpine
   - Created nginx.conf with SPA routing and WASM mime types
   - Updated Dockerfile for static file serving
   - Reduced image size from ~150MB to ~25MB
   - Changed port from 3000 to 80 (standard HTTP)
   - Simplified docker-compose.yml (removed pastel-api service)

4. **Documentation Updates:**
   - Updated README.md with WASM benefits and deployment options
   - Added Key Benefits section highlighting zero-latency features
   - Rewrote deployment section for static hosting platforms
   - Updated CLAUDE.md tech stack and architecture
   - Removed obsolete docs: DEV_SETUP.md, DOCKER.md, IMPLEMENTATION_PLAN.md

**Benefits:**
- 🚀 Zero Latency - All operations run locally via WebAssembly
- 📱 Offline First - Works completely offline after initial load
- 🌐 No Backend - Fully static, deploy anywhere
- ⚡ Fast - Native-speed color operations in browser
- 📦 Small - 2.2MB total (130KB WASM, 2.07MB HTML/CSS/JS)

**Deployment:**
Can now be deployed to any static hosting platform:
- Vercel, Netlify, Cloudflare Pages (zero config)
- GitHub Pages, S3, CDN
- Self-hosted nginx/Apache
- Docker (optional, nginx-based)

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

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

next.config.ts

@@ -3,17 +3,17 @@ import type { NextConfig } from 'next';
 const nextConfig: NextConfig = {
   reactStrictMode: true,
 
-  // Enable standalone output for Docker
-  output: 'standalone',
+  // Enable static export for WASM-based app (no backend required)
+  output: 'export',
 
   // React Compiler disabled for now (requires babel-plugin-react-compiler)
   // experimental: {
   //   reactCompiler: true,
   // },
 
-  // Image optimization
+  // Disable image optimization for static export
   images: {
-    formats: ['image/avif', 'image/webp'],
+    unoptimized: true,
   },
 
   // Bundle analyzer (conditional)