Add SwiftUI gesture inspector and target overlay controls

[Kyle-Ye]

Adds a Gestures inspector for connected SwiftUI targets, making recorded responder trees, gesture phases, hit tests, bindings, and raw logs available in the Mac app alongside target-app highlighting.

Companion Server implementation: https://github.com/LookInsideApp/LookInside-Server/pull/7. Capture requires the Server's gesture-debug capability.

Changes

• Add the Gestures toolbar entry and a capture session that handles capability checks, incoming events, status, bounded history, and lifecycle cleanup.
• Show event history, responder/gesture/binding trees, reported geometry, and reconstructed content-shape details, with explicit notes when exact paths or parameters are unavailable.
• Add capture controls, Follow latest, JSON export, persistent gesture-border controls, border counts, and Clear Borders.
• Mirror the shared capability fields and new gesture message identifiers from the Server while retaining existing protocol identifiers.

Validation

• After rebasing onto origin/main: the macOS Debug app built successfully with Xcode 27 and the updated SwiftyXPC dependency.
• Manually verified capture, live event/tree details, target borders, JSON export, and stop/cleanup with macOS and iOS Simulator fixtures.
• The companion Server change covers shape rendering and scene cleanup with unit tests and macOS/iOS UI tests. Swift formatting checks passed for all five new inspector files.

Capture details represent observed SwiftUI logs. Reconstructed shapes and asynchronous capture retain the limitations described by the Server and shown in the inspector.