Use File Open path for native SVG drops

Route native SVG drops through the same reader as File > Open.

README.md

@@ -169,6 +169,11 @@ Graphics Processor** and restart. If a graphics processor can't show the window,
 next one. To pick one when starting the app, set `WGPU_POWER_PREF=high` (or `low`), or `WGPU_ADAPTER_NAME` to part of
 its name, such as `WGPU_ADAPTER_NAME=nvidia` (see [`docs/development.md`](docs/development.md#desktop-graphics-processor)).
 
+On native Wayland, winit 0.30 does not deliver dropped files. To open an SVG, use File › Open;
+to place artwork in the current document, copy and paste the file in a file manager; or run
+under XWayland (`WAYLAND_DISPLAY= vectorcraft`) for file drag-and-drop
+(see [`docs/development.md`](docs/development.md#linux-wayland-and-x11)).
+
 On Linux under KDE Plasma 6.3 or later with Wayland, a drawing tablet's pen moves the cursor but VectorCraft doesn't
 respond to it yet (#491). Start the app under XWayland instead: `WAYLAND_DISPLAY= vectorcraft` (see
 [`docs/development.md`](docs/development.md#linux-wayland-and-x11)).