Picker input starts in each platform UI, while protocol state lives in
LibWebView. Route movement, primary clicks, Escape, and leave events
through the WebView picker API so each frontend drives the same hit-test
and picker-event path.
The selected click is consumed because picker mode uses it to choose an
element for DevTools rather than activate page content.
AppKit routes normal mouse input through WebViewBridge, which converts
view points to device pixels before forwarding to LibWeb. Picker input
bypasses that enqueue path, so apply the same scaling before requesting
a picker hit test.