Convert public directory from submodule to normal directory

- Remove public from git submodule tracking
- Add all public directory contents as regular files
- Fixes GitHub Actions error: "No url found for submodule path 'public' in .gitmodules"

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

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

public/functions/_middleware.js

@@ -0,0 +1,20 @@
+// Respond to OPTIONS method
+export const onRequestOptions: PagesFunction = async () => {
+  return new Response(null, {
+    status: 204,
+    headers: {
+      'Access-Control-Allow-Origin': '*',
+      'Access-Control-Allow-Headers': '*',
+      'Access-Control-Allow-Methods': 'GET, OPTIONS',
+      'Access-Control-Max-Age': '86400',
+    },
+  });
+};
+
+// Set CORS to all /api responses
+export const onRequest: PagesFunction = async ({ next }) => {
+  const response = await next();
+  response.headers.set('Access-Control-Allow-Origin', '*');
+  response.headers.set('Access-Control-Max-Age', '86400');
+  return response;
+};