Integrated tab bar UI elements (#7853)

## Summary

The current help / feedback is often overlooked by users, this adds a
setting that makes it more visible moving it up into the tab bar and
moves the user login/profile button out of the "action bar" into the tab
bar.

## Changes
- Add 'Comfy.UI.TabBarLayout' setting with Default/Integrated options
- Move Help & User controls to tab bar when Integrated mode is enabled
- Extract help center logic into shared useHelpCenter composable

## Screenshots (if applicable)

<img width="515" height="540" alt="image"
src="https://github.com/user-attachments/assets/c9e6057f-4fb1-4da6-b25d-9df4b19be31a"
/>
<img width="835" height="268" alt="image"
src="https://github.com/user-attachments/assets/24afc0e8-97eb-45cf-af86-15a9b464e9a8"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7853-Integrated-tab-bar-UI-elements-2df6d73d365081b1beb8f7c641c2fa43)
by [Unito](https://www.unito.io)

---------

Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

src/locales/en/main.json

@@ -838,6 +838,7 @@
     "customNodesManager": "Custom Nodes Manager",
     "settings": "Settings",
     "help": "Help",
+    "helpAndFeedback": "Help & Feedback",
     "queue": "Queue Panel"
   },
   "tabMenu": {

src/locales/en/settings.json

@@ -369,6 +369,14 @@
   "Comfy_TreeExplorer_ItemPadding": {
     "name": "Tree explorer item padding"
   },
+  "Comfy_UI_TabBarLayout": {
+    "name": "Tab Bar Layout",
+    "tooltip": "Controls the layout of the tab bar. \"Integrated\" moves Help and User controls into the tab bar area.",
+    "options": {
+      "Default": "Default",
+      "Integrated": "Integrated"
+    }
+  },
   "Comfy_UseNewMenu": {
     "name": "Use new menu",
     "tooltip": "Enable the redesigned top menu bar.",