feat/fix: App mode QA updates (#9439)

## Summary

Various fixes from app mode QA

## Changes

- **What**: 
- fix: prevent inserting nodes from workflow/apps sidebar tabs
- fix: hide json extension in workflow tab
- fix: hide apps nav button in apps tab when already in apps mode
- fix: center text on arrange page
- fix: prevent IoItems from "jumping" due to stale transform after drag
and drop op
- fix: refactor side panels and add custom stable pixel based sizing
- fix: make outputs/inputs lists in app builder scrollable
- fix: fix rerun not working correctly

- feat: add text to interrupt button
- feat: add enter app mode button to builder toolbar
- feat: add tooltip to download button on linear view
- feat: show last output of workflow in arrange tab if available
- feat: show download count in download all button, hide if only 1 asset
to download

## Review Focus

- Rerun - I am not sure why it was triggering widget actions, removing
it seemed like the correct fix
- useStablePrimeVueSplitter - this is a workaround for the fact it uses
percent sizing, I also tried switching to reka-ui splitters, but they
also only support % sizing in our version [pixel based looks to have
been added in a newer version, will log an issue to upgrade & replace
splitters with this]


## Screenshots (if applicable)

<img width="1314" height="1129" alt="image"
src="https://github.com/user-attachments/assets/c430f9d6-7c29-4853-803e-5b6fe7086fca"
/>
<img width="511" height="283" alt="image"
src="https://github.com/user-attachments/assets/b7e594d4-70a1-41e3-8ba1-78512f2a5c8b"
/>
<img width="254" height="232" alt="image"
src="https://github.com/user-attachments/assets/1d146399-39ea-4b0e-928c-340b74957535"
/>
<img width="487" height="198" alt="image"
src="https://github.com/user-attachments/assets/e2ba7f5d-8ff5-47f4-9526-61ebb99514b8"
/>
<img width="378" height="647" alt="image"
src="https://github.com/user-attachments/assets/a47a3054-9320-4327-bdc0-b0a16e19f83d"
/>
<img width="1016" height="476" alt="image"
src="https://github.com/user-attachments/assets/479ae50e-d380-4d56-a5c9-5df142b14ed0"
/>


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9439-feat-fix-App-mode-QA-updates-31a6d73d365081b38337d63207b88817)
by [Unito](https://www.unito.io)

src/components/sidebar/tabs/AppsSidebarTab.vue

@@ -2,7 +2,6 @@
   <BaseWorkflowsSidebarTab
     :title="$t('linearMode.appModeToolbar.apps')"
     :filter="isAppWorkflow"
-    :label-transform="stripAppJsonSuffix"
     hide-leaf-icon
     :search-subject="$t('linearMode.appModeToolbar.apps')"
     data-testid="apps-sidebar"
@@ -18,8 +17,14 @@
       <NoResultsPlaceholder
         button-variant="secondary"
         text-class="text-muted-foreground text-sm"
-        :message="$t('linearMode.appModeToolbar.appsEmptyMessage')"
-        :button-label="$t('linearMode.appModeToolbar.enterAppMode')"
+        :message="
+          isAppMode
+            ? $t('linearMode.appModeToolbar.appsEmptyMessage')
+            : `${$t('linearMode.appModeToolbar.appsEmptyMessage')}\n${$t('linearMode.appModeToolbar.appsEmptyMessageAction')}`
+        "
+        :button-label="
+          isAppMode ? undefined : $t('linearMode.appModeToolbar.enterAppMode')
+        "
         @action="enterAppMode"
       />
     </template>
@@ -32,16 +37,12 @@ import BaseWorkflowsSidebarTab from '@/components/sidebar/tabs/BaseWorkflowsSide
 import { useAppMode } from '@/composables/useAppMode'
 import type { ComfyWorkflow } from '@/platform/workflow/management/stores/workflowStore'
 
-const { setMode } = useAppMode()
+const { isAppMode, setMode } = useAppMode()
 
 function isAppWorkflow(workflow: ComfyWorkflow): boolean {
   return workflow.suffix === 'app.json'
 }
 
-function stripAppJsonSuffix(label: string): string {
-  return label.replace(/\.app\.json$/i, '')
-}
-
 function enterAppMode() {
   setMode('app')
 }