fix: stabilize workflow board and loop recovery

packages/dashboard/app/components/WorkflowNodeEditor.css

@@ -259,6 +259,10 @@
   min-width: 0;
 }
 
+.wf-editor-mobile-back {
+  display: none;
+}
+
 .wf-editor-canvas-empty {
   flex: 1;
   justify-content: center;
@@ -1185,14 +1189,55 @@
     flex-direction: column;
   }
 
-  .wf-editor-sidebar {
+  .wf-editor-body--list-stage .wf-editor-sidebar {
+    display: flex;
     width: 100%;
-    max-height: 30vh;
+    flex: 1 1 auto;
+    max-height: none;
     border-right: none;
-    border-bottom: 1px solid var(--border);
+    border-bottom: none;
     overflow-y: auto;
   }
 
+  .wf-editor-body--list-stage .wf-editor-canvas-wrap,
+  .wf-editor-body--list-stage .wf-editor-inspector {
+    display: none;
+  }
+
+  .wf-editor-body--editor-stage .wf-editor-sidebar {
+    display: none;
+  }
+
+  .wf-editor-body--editor-stage .wf-editor-canvas-wrap {
+    display: flex;
+    flex: 1 1 auto;
+    min-height: 0;
+  }
+
+  .wf-editor-body--editor-stage .wf-editor-inspector {
+    width: 100%;
+    min-width: 0;
+    max-height: 45vh;
+    border-left: none;
+    border-top: 1px solid var(--border);
+    overflow-y: auto;
+  }
+
+  .wf-editor-mobile-back {
+    display: inline-flex;
+    align-items: center;
+    align-self: flex-start;
+    gap: var(--space-xs);
+    margin: var(--space-sm) var(--space-sm) 0;
+    padding: 5px 8px;
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    background: var(--surface);
+    color: var(--text);
+    font-size: 0.8rem;
+    cursor: pointer;
+  }
+
   .wf-editor-sidebar .wf-column-panel {
     width: 100%;
     min-width: 0;
@@ -1211,7 +1256,7 @@
 
   .wf-editor-canvas-wrap {
     flex: 1 1 auto;
-    min-height: 40vh;
+    min-height: 0;
   }
 
   .wf-template-list {