App builder exit updates (#9218)

## Summary

- remove exit builder button from right panel
- add builder exit button to bottom of canvas
- add builder menu with save & exit in top left

## Screenshots (if applicable)

<img width="1544" height="998" alt="image"
src="https://github.com/user-attachments/assets/f5deadc5-2bf5-4729-b644-2b6a815b9975"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9218-App-builder-exit-updates-3126d73d365081a0bf1adf92e1171060)
by [Unito](https://www.unito.io)

src/views/GraphView.vue

@@ -13,7 +13,11 @@
       <GraphCanvas @ready="onGraphReady" />
     </div>
     <LinearView v-if="linearMode" />
-    <BuilderToolbar v-if="isBuilderMode" />
+    <template v-if="isBuilderMode">
+      <BuilderToolbar />
+      <BuilderMenu />
+      <BuilderExitButton />
+    </template>
   </div>
 
   <GlobalToast />
@@ -87,6 +91,8 @@ import { useBottomPanelStore } from '@/stores/workspace/bottomPanelStore'
 import { useColorPaletteStore } from '@/stores/workspace/colorPaletteStore'
 import { useSidebarTabStore } from '@/stores/workspace/sidebarTabStore'
 import { electronAPI } from '@/utils/envUtil'
+import BuilderExitButton from '@/components/builder/BuilderExitButton.vue'
+import BuilderMenu from '@/components/builder/BuilderMenu.vue'
 import BuilderToolbar from '@/components/builder/BuilderToolbar.vue'
 import LinearView from '@/views/LinearView.vue'
 import ManagerProgressToast from '@/workbench/extensions/manager/components/ManagerProgressToast.vue'