Add shadertoy-server example for WebGL shader rendering (#226)

Introduces a new MCP App example that renders ShaderToy-compatible GLSL
fragment shaders in real-time using WebGL 2.0 and ShaderToyLite.js.

Features:
- Standard ShaderToy uniforms (`iTime`, `iResolution`, `iMouse`, etc.)
- Multi-pass rendering with buffers A-D for feedback effects
- Shader compilation error overlay

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

examples/shadertoy-server/package.json

@@ -0,0 +1,43 @@
+{
+  "name": "@modelcontextprotocol/server-shadertoy",
+  "version": "0.1.0",
+  "type": "module",
+  "description": "MCP App Server example for rendering ShaderToy-compatible GLSL shaders",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/modelcontextprotocol/ext-apps",
+    "directory": "examples/shadertoy-server"
+  },
+  "license": "MIT",
+  "main": "server.ts",
+  "files": [
+    "server.ts",
+    "server-utils.ts",
+    "dist"
+  ],
+  "scripts": {
+    "build": "tsc --noEmit && cross-env INPUT=mcp-app.html vite build",
+    "watch": "cross-env INPUT=mcp-app.html vite build --watch",
+    "serve": "bun server.ts",
+    "start": "cross-env NODE_ENV=development npm run build && npm run serve",
+    "dev": "cross-env NODE_ENV=development concurrently 'npm run watch' 'npm run serve'",
+    "prepublishOnly": "npm run build"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/ext-apps": "^0.3.1",
+    "@modelcontextprotocol/sdk": "^1.24.0",
+    "zod": "^4.1.13"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.19",
+    "@types/express": "^5.0.0",
+    "@types/node": "^22.0.0",
+    "concurrently": "^9.2.1",
+    "cors": "^2.8.5",
+    "cross-env": "^10.1.0",
+    "express": "^5.1.0",
+    "typescript": "^5.9.3",
+    "vite": "^6.0.0",
+    "vite-plugin-singlefile": "^2.3.0"
+  }
+}