- add cron expression builder to sidebar and tools.json, add screenshot

Author: TobiasMue91

data/tools.json

@@ -1241,5 +1241,16 @@
     "aiPowered": false,
     "featured": false,
     "date": "2025-03-30"
+  },
+  {
+    "id": "cron_expression_builder",
+    "title": "Cron Expression Builder",
+    "description": "Visual interface to create, validate, and understand cron job scheduling expressions.",
+    "url": "tools/cron_expression_builder.html",
+    "screenshot": "screenshots/screenshot_164.png",
+    "type": "tool",
+    "aiPowered": false,
+    "featured": false,
+    "date": "2025-03-30"
   }
 ]

screenshots/screenshot_164.png

@@ -249,6 +249,7 @@ <h2>Tools by ChatGPT</h2>
       <li><a href="/tools/cps_test.html">CPS Test</a></li>
       <li><a href="/tools/ai_code_explainer.html">AI Code Explainer</a></li>
       <li><a href="/tools/web_accessibility_checker.html">Web Accessibility Checker</a></li>
+      <li><a href="/tools/cron_expression_builder.html">Cron Expression Builder</a></li>
 <!-- end -->
     </ul>
   </div>