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/locales/en/main.json

@@ -3160,12 +3160,13 @@
     "runCount": "Number of runs",
     "rerun": "Rerun",
     "reuseParameters": "Reuse Parameters",
-    "downloadAll": "Download All",
+    "downloadAll": "Download {count} assets from this run",
     "viewJob": "View Job",
     "enterNodeGraph": "Enter node graph",
     "emptyWorkflowExplanation": "Your workflow is empty. You need some nodes first to start building an app.",
     "backToWorkflow": "Back to workflow",
     "loadTemplate": "Load a template",
+    "cancelThisRun": "Cancel this run",
     "welcome": {
       "title": "App Mode",
       "message": "A simplified view that hides the node graph so you can focus on creating.",
@@ -3177,7 +3178,8 @@
     "appModeToolbar": {
       "appBuilder": "App builder",
       "apps": "Apps",
-      "appsEmptyMessage": "Saved apps will show up here.\nClick below to build your first app.",
+      "appsEmptyMessage": "Saved apps will show up here.",
+      "appsEmptyMessageAction": "Click below to build your first app.",
       "enterAppMode": "Enter app mode"
     },
     "arrange": {
@@ -3519,6 +3521,7 @@
     "emptyWorkflowPrompt": "Do you want to start with a template?"
   },
   "builderMenu": {
+    "enterAppMode": "Enter app mode",
     "exitAppBuilder": "Exit app builder"
   }
 }