Fix FrameViewAnnotationsExample: account for shadow in bounding box (#9555)

## Summary
- Wrap annotation view in a container with padding to account for shadow
extent
- This ensures the annotation's bounding box includes the shadow area,
preventing premature hiding during map panning

## Problem
View annotations with shadows were disappearing before the shadow
visually left the screen. This happened because `ViewAnnotation` uses
`systemLayoutSizeFitting()` to determine the bounding box, which doesn't
account for `CALayer` shadow properties.

## Solution
Wrap the card view in a transparent container with padding calculated
from shadow parameters:
```swift
let shadowPadding = shadowRadius * 2 + max(abs(shadowOffset.width), abs(shadowOffset.height))
```

This makes the bounding box large enough to include the full shadow
extent.

Related:
- mapbox/mapbox-sdk#9460

| Before | After |
|--------|--------|
| <video
src="https://github.com/user-attachments/assets/304b4b61-74b5-460f-a5b0-8638b30d6413"
/> | <video
src="https://github.com/user-attachments/assets/f50e812b-6b6a-4d87-b4c8-58e4cee27d90"
/> |

cc @mapbox/sdk-platform
cc @mapbox/maps-ios

GitOrigin-RevId: 0ef27e5c14073b9f433cded608831c14ecccb1fb

Author: OdNairy

CHANGELOG.md

@@ -6,6 +6,9 @@ Mapbox welcomes participation and contributions from everyone.
 
 ### Features ✨ and improvements 🏁
 * Introduce experimental `queryRenderedRasterValues` API for querying the rendered raster array value at a point on the map.
+
+### Bug fixes 🐞
+* Fix `FrameViewAnnotationsExample` annotations disappearing before shadow leaves the screen.
 ## 11.18.0 - 15 January, 2026
 
 ### Bug fixes 🐞

Sources/Examples/All Examples/Annotations/FrameViewAnnotationsExample.swift

@@ -134,24 +134,43 @@ final class FrameViewAnnotationsExample: UIViewController, ExampleProtocol {
 
     private func addAnnotations() {
         func makeView(text: String) -> UIView {
-            let view = UIView()
-            view.backgroundColor = .white
-            view.layer.shadowOpacity = 0.25
-            view.layer.shadowRadius = 8
-            view.layer.shadowOffset = CGSize(width: 0, height: 2)
-            view.layer.cornerRadius = 8
+            let shadowRadius: CGFloat = 8
+            let shadowOffset = CGSize(width: 0, height: 2)
+            // Shadow blur extends beyond shadowRadius. Use ~2x multiplier for smooth fade.
+            let shadowPadding = shadowRadius * 2 + max(abs(shadowOffset.width), abs(shadowOffset.height))
+            let labelPadding: CGFloat = 4
+
+            let container = UIView()
+
+            let card = UIView()
+            card.backgroundColor = .white
+            card.layer.shadowOpacity = 0.25
+            card.layer.shadowRadius = shadowRadius
+            card.layer.shadowOffset = shadowOffset
+            card.layer.cornerRadius = 8
+            card.translatesAutoresizingMaskIntoConstraints = false
+
             let label = UILabel()
             label.text = text
             label.textColor = .black
             label.translatesAutoresizingMaskIntoConstraints = false
-            view.addSubview(label)
+
+            card.addSubview(label)
+            container.addSubview(card)
+
             NSLayoutConstraint.activate([
-                label.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 4),
-                label.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -4),
-                label.topAnchor.constraint(equalTo: view.topAnchor, constant: 4),
-                label.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: -4),
+                label.leadingAnchor.constraint(equalTo: card.leadingAnchor, constant: labelPadding),
+                label.trailingAnchor.constraint(equalTo: card.trailingAnchor, constant: -labelPadding),
+                label.topAnchor.constraint(equalTo: card.topAnchor, constant: labelPadding),
+                label.bottomAnchor.constraint(equalTo: card.bottomAnchor, constant: -labelPadding),
+
+                card.leadingAnchor.constraint(equalTo: container.leadingAnchor, constant: shadowPadding),
+                card.trailingAnchor.constraint(equalTo: container.trailingAnchor, constant: -shadowPadding),
+                card.topAnchor.constraint(equalTo: container.topAnchor, constant: shadowPadding),
+                card.bottomAnchor.constraint(equalTo: container.bottomAnchor, constant: -shadowPadding),
             ])
-            return view
+
+            return container
         }
 
         self.annotations = annotationData.map {