Files dragged from outside onto the Pages panel are inserted at the gap under the pointer (with a drop indicator) instead of opening as new documents. Files dropped beside the panel still open as before.
On Windows, winit sends no pointer moves while files are dragged over the window, so the cursor is read with GetPhysicalCursorPos (winsafe "user" feature). This also makes the page grid show and use the gap under the pointer during a drag on Windows. Linux/BSD still have no pointer during a drag and keep the existing fallback.
Tests: two new kittest cases in tests/editing.rs (drop on the panel inserts at the gap / at the end; drop beside the panel opens a document). The Windows cursor path was checked by hand.
tylerstoltz
5105eb732c