fix: use standard size-4 for blueprint action icons (#10992)

## Summary

Fix undersized delete and edit icons on user blueprint items in the node
library sidebar.

## Changes

- **What**: Changed blueprint action icons (trash, edit) from `size-3.5`
(14px) to `size-4` (16px), matching the standard icon size used across
the codebase.

## Review Focus

Trivial sizing fix — `size-4` is the codebase-wide convention for
iconify icons in buttons, and what the button base styles default SVGs
to.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10992-fix-use-standard-size-4-for-blueprint-action-icons-33d6d73d365081be8c65f9e2a7b1d6ec)
by [Unito](https://www.unito.io)

src/components/sidebar/tabs/nodeLibrary/NodeTreeLeaf.vue

@@ -25,7 +25,7 @@
           :aria-label="$t('g.delete')"
           @click.stop="deleteBlueprint"
         >
-          <i class="icon-[lucide--trash-2] size-3.5" />
+          <i class="icon-[lucide--trash-2] size-4" />
         </Button>
         <Button
           variant="muted-textonly"
@@ -33,7 +33,7 @@
           :aria-label="$t('g.edit')"
           @click.stop="editBlueprint"
         >
-          <i class="icon-[lucide--square-pen] size-3.5" />
+          <i class="icon-[lucide--square-pen] size-4" />
         </Button>
       </template>
       <template v-else #actions>