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>

app/api/pastel/[...path]/route.ts

@@ -1,122 +0,0 @@
-import { NextRequest, NextResponse } from 'next/server';
-
-/**
- * API Proxy Route for Pastel API
- *
- * This proxy allows runtime configuration of the Pastel API URL
- * without rebuilding the Docker image. The API URL is read from
- * the server-side environment variable at runtime.
- *
- * Client requests go to: /api/pastel/*
- * Proxied to: PASTEL_API_URL/*
- */
-
-const PASTEL_API_URL = process.env.PASTEL_API_URL || 'http://localhost:3001';
-
-export async function GET(
-  request: NextRequest,
-  { params }: { params: Promise<{ path: string[] }> }
-) {
-  const { path } = await params;
-  return proxyRequest(request, path, 'GET');
-}
-
-export async function POST(
-  request: NextRequest,
-  { params }: { params: Promise<{ path: string[] }> }
-) {
-  const { path } = await params;
-  return proxyRequest(request, path, 'POST');
-}
-
-export async function PUT(
-  request: NextRequest,
-  { params }: { params: Promise<{ path: string[] }> }
-) {
-  const { path } = await params;
-  return proxyRequest(request, path, 'PUT');
-}
-
-export async function DELETE(
-  request: NextRequest,
-  { params }: { params: Promise<{ path: string[] }> }
-) {
-  const { path } = await params;
-  return proxyRequest(request, path, 'DELETE');
-}
-
-export async function PATCH(
-  request: NextRequest,
-  { params }: { params: Promise<{ path: string[] }> }
-) {
-  const { path } = await params;
-  return proxyRequest(request, path, 'PATCH');
-}
-
-async function proxyRequest(
-  request: NextRequest,
-  pathSegments: string[],
-  method: string
-) {
-  try {
-    const path = pathSegments.join('/');
-    const targetUrl = `${PASTEL_API_URL}/api/v1/${path}`;
-
-    // Get request body if present
-    const body = method !== 'GET' && method !== 'DELETE'
-      ? await request.text()
-      : undefined;
-
-    // Forward the request to the Pastel API
-    const response = await fetch(targetUrl, {
-      method,
-      headers: {
-        'Content-Type': 'application/json',
-        // Forward relevant headers
-        ...(request.headers.get('accept') && {
-          'Accept': request.headers.get('accept')!
-        }),
-      },
-      body,
-    });
-
-    // Get response data
-    const data = await response.text();
-
-    // Return response with same status and headers
-    return new NextResponse(data, {
-      status: response.status,
-      headers: {
-        'Content-Type': response.headers.get('content-type') || 'application/json',
-        // Add CORS headers if needed
-        'Access-Control-Allow-Origin': '*',
-        'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, PATCH, OPTIONS',
-        'Access-Control-Allow-Headers': 'Content-Type, Authorization',
-      },
-    });
-  } catch (error) {
-    console.error('Proxy error:', error);
-    return NextResponse.json(
-      {
-        success: false,
-        error: {
-          code: 'PROXY_ERROR',
-          message: error instanceof Error ? error.message : 'Failed to proxy request',
-        },
-      },
-      { status: 500 }
-    );
-  }
-}
-
-// Handle OPTIONS requests for CORS
-export async function OPTIONS() {
-  return new NextResponse(null, {
-    status: 204,
-    headers: {
-      'Access-Control-Allow-Origin': '*',
-      'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, PATCH, OPTIONS',
-      'Access-Control-Allow-Headers': 'Content-Type, Authorization',
-    },
-  });
-}