Close zoom menu when toggling minimap visibility (#5974)

## Summary

Closes the zoom menu popup when clicking show/hide minimap to prevent
the menu from remaining open after toggling.

## Changes

- **What**: Adds `close` event emission from `ZoomControlsModal` when
minimap toggle is clicked, wired to `hideModal` in parent
`GraphCanvasMenu`
- **Tests**: Adds unit tests verifying close behavior for minimap toggle
vs other commands

## Review Focus

This fixes the immediate UX issue where the zoom popup remained open
after toggling minimap visibility. However, the minimap toggle's
placement within the zoom menu is **not** ideal—it's not intuitive to
look for minimap controls within zoom controls. This PR addresses the
current UX friction without tackling the broader discoverability issue.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5974-Close-zoom-menu-when-toggling-minimap-visibility-2866d73d365081bdbb0bfeb0da4b8c2b)
by [Unito](https://www.unito.io)

---------

Co-authored-by: DrJKL <DrJKL0424@gmail.com>

src/components/graph/GraphCanvasMenu.vue

@@ -1,6 +1,6 @@
 <template>
   <div>
-    <ZoomControlsModal :visible="isModalVisible" />
+    <ZoomControlsModal :visible="isModalVisible" @close="hideModal" />
 
     <!-- Backdrop -->
     <div