update minimap and canvas bg to use menu color tokens (#6589)

Update minimap and graph canvas menu (bottom right) to use menu tokens.
Change canvas BG color on default dark theme.

<img width="3840" height="2029" alt="image"
src="https://github.com/user-attachments/assets/6d168981-df27-40c0-829c-59150b8a6a12"
/>


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6589-wip-Style-graph-canvas-color-2a26d73d365081cb88c4c4bdb2b6d3a5)
by [Unito](https://www.unito.io)

---------

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

src/components/topbar/CurrentUserButton.vue

@@ -10,7 +10,7 @@
       @click="popover?.toggle($event)"
     >
       <div
-        class="flex items-center gap-1 rounded-full hover:bg-[var(--interface-button-hover-surface)]"
+        class="flex items-center gap-1 rounded-full hover:bg-interface-button-hover-surface"
       >
         <UserAvatar :photo-url="photoURL" />
 

src/components/topbar/LoginButton.vue

@@ -4,7 +4,7 @@
     outlined
     rounded
     severity="secondary"
-    class="size-8 border-black/50 bg-transparent text-black hover:bg-[var(--interface-panel-hover-surface)] dark-theme:border-white/50 dark-theme:text-white"
+    class="size-8 border-black/50 bg-transparent text-black hover:bg-interface-panel-hover-surface dark-theme:border-white/50 dark-theme:text-white"
     @click="handleSignIn()"
     @mouseenter="showPopover"
     @mouseleave="hidePopover"