Return Turnstile verification details

functions/api/contact.ts

@@ -57,11 +57,33 @@ const handlePost: PagesFunction<Env> = async ({ request, env }) => {
     );
     const verifyResult = (await verifyResponse.json()) as {
         success?: boolean;
+        "error-codes"?: string[];
+        messages?: string[];
+        hostname?: string;
+        action?: string;
+        cdata?: string;
     };
 
     if (!verifyResult.success) {
+        const details = [
+            verifyResult["error-codes"]?.length
+                ? `codes=${verifyResult["error-codes"].join(",")}`
+                : "",
+            verifyResult.messages?.length
+                ? `messages=${verifyResult.messages.join(",")}`
+                : "",
+            verifyResult.hostname ? `hostname=${verifyResult.hostname}` : "",
+            verifyResult.action ? `action=${verifyResult.action}` : "",
+        ]
+            .filter(Boolean)
+            .join(" | ")
+            .slice(0, 500);
         return jsonResponse(
-            { ok: false, error: "Turnstile verification failed." },
+            {
+                ok: false,
+                error: "Turnstile verification failed.",
+                details: details || undefined,
+            },
             400,
         );
     }