Fillet UI (#2718)

* draft: fillet ast mod + test

* Kurt's rejig

* playwright

* update button enable logic

* remove fillet button in production build

* A snapshot a day keeps the bugs away! 📷🐛 (OS: ubuntu)

* trigger CI

* fix typo

* give a way to turn on fillets

---------

Co-authored-by: max-mrgrsk <margorskyi@gmail.com>
Co-authored-by: max-mrgrsk <156543465+max-mrgrsk@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

src/components/CustomIcon.tsx

@@ -187,6 +187,22 @@ const CustomIconMap = {
       />
     </svg>
   ),
+  fillet: (
+    <svg viewBox="0 0 20 20" fill="none" xmlns="http://www.w3.org/2000/svg">
+      <path
+        fillRule="evenodd"
+        clipRule="evenodd"
+        d="M8 5H5V15H15V12C15 8.13401 11.866 5 8 5ZM5 4H4V5V15V16H5H15H16V15V12C16 7.58172 12.4183 4 8 4H5Z"
+        fill="currentColor"
+      />
+      <path
+        fillRule="evenodd"
+        clipRule="evenodd"
+        d="M4.5 3.5H5.5H8.5C12.9183 3.5 16.5 7.08172 16.5 11.5V14.5V15.5H16V12C16 7.58172 12.4182 4 7.99996 4H4.5V3.5Z"
+        fill="currentColor"
+      />
+    </svg>
+  ),
   file: (
     <svg viewBox="0 0 20 20" fill="none" xmlns="http://www.w3.org/2000/svg">
       <path