fix: center ComfyUI logo in sidebar menu button with chevron (#9722)

## Summary

Center the ComfyUI logo in the sidebar menu button after chevron icon
was added, and add padding to floating sidebar item groups.

## Changes

Before / after:
<img width="127" height="417" alt="image"
src="https://github.com/user-attachments/assets/aa327fd9-5550-49aa-b28d-a90435e9d1bc"
/>


- **What**: Use negative margin on chevron icon so it doesn't affect
logo centering. Add `p-0.5` padding to floating sidebar item groups.

## Review Focus

Visual alignment of the logo in both floating and connected sidebar
modes.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9722-fix-center-ComfyUI-logo-in-sidebar-menu-button-with-chevron-31f6d73d3650811a9392cda3070310f9)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: Alexander Brown <drjkl@comfy.org>
Co-authored-by: GitHub Action <action@github.com>

src/components/sidebar/ComfyMenuButton.vue

@@ -11,13 +11,15 @@
     }"
     @click="onLogoMenuClick($event)"
   >
-    <div class="flex items-center gap-0.5">
+    <div class="grid place-items-center-safe gap-0.5">
+      <i
+        class="col-span-full row-span-full icon-[lucide--chevron-down] size-3 translate-x-4 text-muted-foreground"
+      />
       <ComfyLogo
         alt="ComfyUI Logo"
-        class="comfyui-logo h-[18px] w-[18px]"
+        class="comfyui-logo col-span-full row-span-full size-4.5"
         mode="fill"
       />
-      <i class="icon-[lucide--chevron-down] size-3 text-muted-foreground" />
     </div>
   </div>