Add nearby POIs to Add-to-Day sheet and improve PlaceSearchSheet empty state

- Add mapItem field to POISearchService.POI for Apple Maps integration
- Merge description + location into single combined card in QuickAddItemSheet
- Auto-load nearby POIs when regionCoordinate is available, with detail sheet
- Create POIDetailSheet with map preview, metadata, and one-tap add-to-day
- Add poiAddedToDay/poiDetailViewed analytics events
- Add initial state to PlaceSearchSheet with search suggestions and flow layout

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

SportsTime/Export/Services/POISearchService.swift

@@ -13,13 +13,14 @@ actor POISearchService {
 
     // MARK: - Types
 
-    struct POI: Identifiable, Hashable {
+    struct POI: Identifiable, Hashable, @unchecked Sendable {
         let id: UUID
         let name: String
         let category: POICategory
         let coordinate: CLLocationCoordinate2D
         let distanceMeters: Double
         let address: String?
+        let mapItem: MKMapItem?
 
         var formattedDistance: String {
             let miles = distanceMeters * 0.000621371
@@ -218,7 +219,8 @@ actor POISearchService {
                 category: category,
                 coordinate: itemCoordinate,
                 distanceMeters: distance,
-                address: formatAddress(item)
+                address: formatAddress(item),
+                mapItem: item
             )
         }