Add loading wheel for editor

packages/website/src/lib/Editor.svelte

@@ -209,6 +209,56 @@
         outline: none;
     }
 
+    .scm-waiting {
+        padding: 4px 2px 4px 6px;
+        position: relative;
+    }
+    .scm-waiting__loading {
+        position: absolute;
+        top: 0;
+        left: 0;
+        bottom: 0;
+        right: 0;
+        background-color: var(--shadow-color);
+    }
+
+    .scm-loading {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+    }
+    .scm-loading__spinner {
+        width: 1rem;
+        height: 1rem;
+        border-radius: 100%;
+        border: solid 2px var(--theme);
+        border-top-color: transparent;
+        margin-right: 0.75rem;
+        animation: spin 1s linear infinite;
+    }
+    .scm-loading__text {
+        font-family: sans-serif;
+    }
+    .scm-pre {
+        font-size: 0.85rem;
+        font-family: monospace;
+        tab-size: 2;
+        -moz-tab-size: 2;
+        resize: none;
+        pointer-events: none;
+        user-select: none;
+        overflow: auto;
+    }
+
+    @keyframes spin {
+        0% {
+            transform: rotate(0deg);
+        }
+        100% {
+            transform: rotate(360deg);
+        }
+    }
+
     :global(.editor-wrapper .cm-scroller, .editor-wrapper .cm-editor) {
         min-height: 200px;
         border-bottom-left-radius: var(--border-radius);