App mode - Unify menus - 2 (#9023)

## Summary

Updates subgraph breadcrumbs menu, workflow tabs context menu & linear
mode menu to use a single implementation.
Adds new menu items for enter/exit app mode  
Hides menu when in builder mode

## Changes

- **What**: Changes the components to use either a reka-ui context menu
or dropdown, with a standard inner list
- **Breaking**: Remove existing linear toggle from sidebar as it is now
in the menu


## Screenshots (if applicable)
It looks basically identical other than the icon changes based on mode:

In Graph Mode:
<img width="261" height="497" alt="image"
src="https://github.com/user-attachments/assets/eb9968a2-b528-4e21-9e14-ab4a67e717ae"
/>

In App Mode:
<img width="254" height="499" alt="image"
src="https://github.com/user-attachments/assets/54a89fab-e7b2-4cb0-bcb7-43d6d076ac83"
/>

Right click tab:
<img width="321" height="564" alt="image"
src="https://github.com/user-attachments/assets/c12c7d64-2dba-45bb-be76-2615f3e38cc6"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9023-App-mode-Unify-menus-2-30d6d73d36508162bfc0e308d5f705de)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/components/sidebar/SideToolbar.vue

@@ -45,9 +45,6 @@
         <SidebarBottomPanelToggleButton v-if="!isCloud" :is-small="isSmall" />
         <SidebarShortcutsToggleButton :is-small="isSmall" />
         <SidebarSettingsButton :is-small="isSmall" />
-        <ModeToggle
-          v-if="menuItemStore.hasSeenLinear || flags.linearToggleEnabled"
-        />
       </div>
     </div>
     <HelpCenterPopups :is-small="isSmall" />
@@ -62,18 +59,15 @@ import { useI18n } from 'vue-i18n'
 
 import HelpCenterPopups from '@/components/helpcenter/HelpCenterPopups.vue'
 import ComfyMenuButton from '@/components/sidebar/ComfyMenuButton.vue'
-import ModeToggle from '@/components/sidebar/ModeToggle.vue'
 import SidebarBottomPanelToggleButton from '@/components/sidebar/SidebarBottomPanelToggleButton.vue'
 import SidebarSettingsButton from '@/components/sidebar/SidebarSettingsButton.vue'
 import SidebarShortcutsToggleButton from '@/components/sidebar/SidebarShortcutsToggleButton.vue'
-import { useFeatureFlags } from '@/composables/useFeatureFlags'
 import { isCloud } from '@/platform/distribution/types'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { useTelemetry } from '@/platform/telemetry'
 import { useCanvasStore } from '@/renderer/core/canvas/canvasStore'
 import { useCommandStore } from '@/stores/commandStore'
 import { useKeybindingStore } from '@/platform/keybindings/keybindingStore'
-import { useMenuItemStore } from '@/stores/menuItemStore'
 import { useUserStore } from '@/stores/userStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
 import type { SidebarTabExtension } from '@/types/extensionTypes'
@@ -90,11 +84,9 @@ const settingStore = useSettingStore()
 const userStore = useUserStore()
 const commandStore = useCommandStore()
 const canvasStore = useCanvasStore()
-const menuItemStore = useMenuItemStore()
 const sideToolbarRef = ref<HTMLElement>()
 const topToolbarRef = ref<HTMLElement>()
 const bottomToolbarRef = ref<HTMLElement>()
-const { flags } = useFeatureFlags()
 
 const isSmall = computed(
   () => settingStore.get('Comfy.Sidebar.Size') === 'small'