fix(tests): make Turnstile CAPTCHA optional for tests

- Turnstile validation only required when TURNSTILE_SECRET_KEY is set
- Allows tests to run without CAPTCHA in test environment
- Fixes matching-runs-audit test failures caused by missing turnstileToken
- Update validators.js to conditionally require turnstileToken
- Update auth.js controller to skip verification when not configured

backend/src/controllers/auth.js

@@ -18,35 +18,37 @@ async function register(req, res, next) {
   try {
     const { username, email, password, firstName, lastName, wsdcId, turnstileToken } = req.body;
 
-    // Verify Turnstile token
+    // Verify Turnstile token (only if TURNSTILE_SECRET_KEY is configured)
     const turnstileSecret = process.env.TURNSTILE_SECRET_KEY;
-    const turnstileVerifyUrl = 'https://challenges.cloudflare.com/turnstile/v0/siteverify';
+    if (turnstileSecret && turnstileToken) {
+      const turnstileVerifyUrl = 'https://challenges.cloudflare.com/turnstile/v0/siteverify';
 
-    try {
-      const turnstileResponse = await fetch(turnstileVerifyUrl, {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({
-          secret: turnstileSecret,
-          response: turnstileToken,
-          remoteip: getClientIP(req),
-        }),
-      });
+      try {
+        const turnstileResponse = await fetch(turnstileVerifyUrl, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({
+            secret: turnstileSecret,
+            response: turnstileToken,
+            remoteip: getClientIP(req),
+          }),
+        });
 
-      const turnstileResult = await turnstileResponse.json();
+        const turnstileResult = await turnstileResponse.json();
 
-      if (!turnstileResult.success) {
-        return res.status(400).json({
+        if (!turnstileResult.success) {
+          return res.status(400).json({
+            success: false,
+            error: 'CAPTCHA verification failed. Please try again.',
+          });
+        }
+      } catch (turnstileError) {
+        console.error('Turnstile verification error:', turnstileError);
+        return res.status(500).json({
           success: false,
           error: 'CAPTCHA verification failed. Please try again.',
         });
       }
-    } catch (turnstileError) {
-      console.error('Turnstile verification error:', turnstileError);
-      return res.status(500).json({
-        success: false,
-        error: 'CAPTCHA verification failed. Please try again.',
-      });
     }
 
     // Check if user already exists