stub in loop operation

web/kiri/index.css

@@ -1448,6 +1448,21 @@ details[open] summary::after {
 #oplist .clock:hover {
     background-color: var(--blue-2);
 }
+#oplist .loop:hover {
+    background-color: rgba(100, 150, 255, 0.35);
+}
+#oplist .in-loop {
+    margin-left: 10px;
+}
+#oplist .in-loop::before {
+    content: "";
+    border: 1px solid var(--blue-2);
+    border-radius: 3px;
+    width: 2px;
+    height: 80%;
+    position: absolute;
+    left: -10px;
+}
 #oplist > div {
     padding: 4px 20px 4px 7px !important;
 }

web/kiri/index.html

@@ -471,6 +471,7 @@
                                     <div title="remove an area of material&#13;inside a defined boundary&#13;sometimes called pocketing">rough</div>
                                     <div title="cutout parts using their shadow outline">outline</div>
                                     <div title="perform operations on using outlines or surfaces&#13;many operations are simple wrappers around this">area</div>
+                                    <div id="loop" title="loop next N operations M times">loop</div>
                                 </div>
                             </div>
                         </div>