Add swipeable photo stacks and native iOS gallery preview (#9259)

## Summary

Replace bubble photo carousels with swipeable, overlapping photo stacks,
with distinct sent/received layouts and a stationary photo count.
Opening and closing the gallery preserves the selected photo. Photo
frames follow the active theme.

Add an opt-in iOS 18+ native zoom gallery
(`BUZZ_NATIVE_PHOTO_ZOOM=true`) with paging, continuous dot scrubbing,
preview-backed loading, Reply/More actions, and Liquid Glass controls on
iOS 26+. The existing gallery remains the fallback. UIKit’s late corner
settling and brief return-transition input lockout remain known preview
limitations.

### Related issue

None found.

### Testing

Validation: full mobile pre-push checks/tests passed on `2b5bac3075`;
light/dark sent/received widget renders verified. Earlier native
simulator checks covered paging, scrubbing, downward close, and Reply.

Snapshots below are actual Flutter widget renders with sample photos
(not device screenshots).

| Before: carousel | After: sent | After: received |
| --- | --- | --- |
| ![Original photo
carousel](https://github.com/user-attachments/assets/9fb13b0a-d2b9-4429-9bb1-396deeb126da)
| ![Sent photo
stack](https://github.com/user-attachments/assets/ab6a3094-5460-45fb-8020-68c454d6474f)
| ![Received photo
stack](https://github.com/user-attachments/assets/0ec2e803-a5b5-4812-8159-2e0585eea199)
|



| Dark mode: sent | Dark mode: received |
| --- | --- |
| ![Dark sent photo
stack](https://github.com/user-attachments/assets/3d4f993a-4e59-4da8-a30b-c6a0c19ad7eb)
| ![Dark received photo
stack](https://github.com/user-attachments/assets/e552070a-e516-434c-ae76-0f8811184d2e)
|

---------

Signed-off-by: kenny lopez <klopez4212@gmail.com>
Co-authored-by: Terp <5856f6900e8e0a4e0ea1f4f8d2ee33e4753d2119bc122f94ecafc660b46c0511@buzz.block.builderlab.xyz>

scripts/test-mobile-photo-zoom.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# Exercise the production native gallery on a booted iOS simulator.
+# Usage: /bin/bash scripts/test-mobile-photo-zoom.sh <simulator-udid>
+set -euo pipefail
+repo_root=$(cd "$(dirname "$0")/.." && pwd)
+device=${1:?Pass a booted iOS simulator UDID}
+flutter_root=$(sed -n 's/^FLUTTER_ROOT=//p' "$repo_root/mobile/ios/Flutter/Generated.xcconfig")
+frameworks="$flutter_root/bin/cache/artifacts/engine/ios/Flutter.xcframework/ios-arm64_x86_64-simulator"
+fixture=$(mktemp -d)
+trap 'rm -r "$fixture"' EXIT
+cat "$repo_root/mobile/ios/Runner/NativePhotoZoomCoordinator.swift" \
+  "$repo_root/mobile/ios/NativeControlTests/NativePhotoZoomTests.swift" > "$fixture/test.swift"
+xcrun --sdk iphonesimulator swiftc -parse-as-library \
+  -sdk "$(xcrun --sdk iphonesimulator --show-sdk-path)" \
+  -target "$(uname -m)-apple-ios18.0-simulator" \
+  -F "$frameworks" -framework Flutter \
+  -Xlinker -rpath -Xlinker "$frameworks" \
+  "$fixture/test.swift" -o "$fixture/photo-zoom-tests"
+xcrun simctl spawn "$device" "$fixture/photo-zoom-tests"