feat: App mode saving rework (#9338)

## Summary

Change app mode changes to be written directly to the workflow on change
instead of requiring explicit save via builder.
Temporary: Adds `.app.json` file extension to app files for
identification since we don't currently have a way to identify them with
metadata
Removes app builder save dialog and replaces it with default mode
selection

## Changes

- **What**: 
- ensure all save locations handle app mode
- remove dirtyLinearData and flushing

- **Breaking**: 
- if people are relying on workflow names and are converting to/from app
mode in the same workflow, they will gain/lose the `.app` part of the
extension

## Screenshots (if applicable)

<img width="689" height="84" alt="image"
src="https://github.com/user-attachments/assets/335596ee-dce9-4e3a-a7b5-f0715c294e41"
/>

<img width="421" height="324" alt="image"
src="https://github.com/user-attachments/assets/ad3cd33c-e9f0-4c30-8874-d4507892fc6b"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9338-feat-App-mode-saving-rework-3176d73d3650813f9ae1f6c5a234da8c)
by [Unito](https://www.unito.io)

src/components/sidebar/tabs/WorkflowsSidebarTab.vue

@@ -161,7 +161,7 @@ import {
 } from '@/platform/workflow/management/stores/workflowStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
 import type { TreeExplorerNode, TreeNode } from '@/types/treeExplorerTypes'
-import { appendJsonExt } from '@/utils/formatUtil'
+import { ensureWorkflowSuffix, getWorkflowSuffix } from '@/utils/formatUtil'
 import { buildTree, sortedTree } from '@/utils/treeUtil'
 
 const settingStore = useSettingStore()
@@ -256,10 +256,11 @@ const renderTreeNode = (
     ? {
         handleClick,
         async handleRename(newName: string) {
+          const suffix = getWorkflowSuffix(workflow.suffix)
           const newPath =
             type === WorkflowTreeType.Browse
-              ? workflow.directory + '/' + appendJsonExt(newName)
-              : ComfyWorkflow.basePath + appendJsonExt(newName)
+              ? workflow.directory + '/' + ensureWorkflowSuffix(newName, suffix)
+              : ComfyWorkflow.basePath + ensureWorkflowSuffix(newName, suffix)
 
           await workflowService.renameWorkflow(workflow, newPath)
         },