feat(activities): peek at a card from the board

Let people read notes, postpone, and mark an activity done beside the card instead of opening the full page.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/src/components/activities/ActivityPostponeSheet.vue

@@ -13,6 +13,8 @@ type PostponeKey = 'h1' | 'tomorrow-am' | 'next-saturday' | 'next-week' | 'custo
 const props = defineProps<{
   dueAt?: string | null;
   saving?: boolean;
+  /** بالاتر از مودال خلاصهٔ فعالیت */
+  overlayZIndex?: number;
 }>();
 
 const emit = defineEmits<{
@@ -154,7 +156,7 @@ onBeforeUnmount(() => {
 
 <template>
   <Teleport to="body">
-    <div class="layer" role="presentation">
+    <div class="layer" role="presentation" :style="overlayZIndex ? { zIndex: overlayZIndex } : undefined">
       <button class="backdrop" type="button" aria-label="بستن" @click="close" />
       <section class="sheet" role="dialog" aria-modal="true" aria-labelledby="postpone-title">
         <div class="handle" aria-hidden="true" />