fix(notes): color the share trigger icon with accent

Scoped styles in HeaderNote don't cross into the ShareNote child
component, so text-base-content painted the icon white/black instead
of matching the other header icons.

src/components/ShareNote.vue

@@ -55,7 +55,7 @@ const copy = async (url: string, label: string) => {
 
 <template>
   <button
-    class="btn btn-ghost btn-circle text-base-content"
+    class="btn btn-ghost btn-circle text-accent"
     title="Share this view"
     aria-label="Share this view"
     onclick="share_modal.showModal()"