feat: show hit target size suggestions in Gesture Debug

[Kyle-Ye]

Gesture Debug now shows a Suggestions tab and warning count for current-page interaction targets below 44 pt in either dimension on iPhone, or 28 pt on Mac, including Catalyst. Each suggestion includes the target size, minimum size, identity, source, and geometry coverage so estimated bounds are visible to the user.

Suggestions use the server's current interaction snapshot rather than historical events, continue updating with borders hidden, and clear on navigation, capture stop, and disconnect. The shared size predicate keeps warnings consistent with target-app border colors, including tolerance for floating-point noise at the threshold. Capture exports retain the interaction snapshot and target platform; older server payloads remain supported.

Validation:

• Hit target rule, platform, lifecycle, export, and capture compatibility model tests passed.
• The macOS Debug app build passed.
• Swift and shell formatting, shared-header consistency, and whitespace checks passed.
• The five-platform build matrix passed for macOS, iOS, iOS Simulator, tvOS, and tvOS Simulator.