Add Vercel configuration for PHP runtime

Configures vercel-php runtime for get.php endpoint and sets up
proper routing for /example directory to enable PHP execution.

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

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

Author: eypsilon

vercel.json

@@ -0,0 +1,17 @@
+{
+  "functions": {
+    "example/get.php": {
+      "runtime": "vercel-php@0.7.1"
+    }
+  },
+  "routes": [
+    {
+      "src": "/example",
+      "dest": "/example/index.html"
+    },
+    {
+      "src": "/example/(.*)",
+      "dest": "/example/$1"
+    }
+  ]
+}