Surface SwiftUI swipe actions via _privateAccessibilityCustomActions

[RoyalPineapple]

Problem

SwiftUI .swipeActions are invisible to the accessibility snapshot parser. VoiceOver surfaces them, but the parser only reads accessibilityCustomActions — which doesn't include swipe actions.

Root cause

UIKit exposes SwiftUI swipe actions through a private API: _privateAccessibilityCustomActions on NSObject. These actions live on the container view (e.g. ListCollectionViewCell), not on the accessibility element proxies inside it:

UICollectionView (List)
 └─ ListCollectionViewCell          ← _privateAccessibilityCustomActions: ["Delete"]
     └─ AccessibilityNode (proxy)   ← accessibilityCustomActions: []
         label: "Row Label"

The parser walks the proxy elements but never looks at the container — so swipe actions are silently dropped.

Solution

Capture private custom actions at the container level in the accessibility model:

AccessibilityContainer
 ├─ customActions: ["Delete"]     ← NEW: captured from _privateAccessibilityCustomActions
 └─ children:
     └─ AccessibilityElement
         └─ customActions: []     ← public actions only (unchanged)

VoiceOver behavior (verified on device)

• Private actions are presented first, before public actions
• No deduplication — if a swipe action and a public action share the same name, both appear
• Private actions on a container are inherited by all child elements

allCustomActions on NSObject matches this ordering and dedup behavior.

What's deferred

Container-aware rendering is future work. The snapshot reference images are identical before and after the parser fix — the model now correctly captures swipe actions, but they won't appear visually in snapshots until the renderer is updated to display container-level actions. Depends on #278 (container visualization) landing first.

Commit structure

Commit	Purpose
99083951 Add SwiftUI swipe actions demo and snapshot tests	Demo + snapshots showing the gap (actions missing)
718686a7 Read swipe actions via _privateAccessibilityCustomActions	Parser fix + unit tests verifying container capture

Dependencies

• Add container visualization for accessibility snapshots #278 — Add container visualization for accessibility snapshots (needed to render container-level actions in snapshots)

Test plan

• SwipeActionsParserTests — container captures private actions, element public actions preserved, multi-element row inheritance, no-swipe baseline
• Snapshot tests pass on iOS 17.5, 18.5, 26.2
• CI green

🤖 Generated with Claude Code