Fix SSG compatibility: fallback /path.html to /path/index.html

Astro and other SSG frameworks generate /path/index.html instead of /path.html.
Added fallback logic so /products resolves to /products/index.html when
/products.html doesn't exist in R2.

src/worker.js

@@ -523,7 +523,17 @@ export default {
     const key = `sites/${customer}${filePath}`;
 
     try {
-      const object = await env.BUCKET.get(key);
+      let object = await env.BUCKET.get(key);
+
+      // Fallback: /path.html → /path/index.html (Astro 등 SSG 호환)
+      if (!object && filePath.endsWith('.html') && filePath !== '/index.html') {
+        const dirPath = filePath.replace(/\.html$/, '/index.html');
+        const dirKey = `sites/${customer}${dirPath}`;
+        object = await env.BUCKET.get(dirKey);
+        if (object) {
+          filePath = dirPath;
+        }
+      }
 
       if (!object) {
         if (filePath === '/index.html') {