Linux: use the X11 backend under XWayland so files can be dropped (#2)

winit 0.30 has no file drag-and-drop on Wayland. DESIGNCRAFT_WAYLAND=1
keeps the native Wayland backend.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -865,6 +865,7 @@ dependencies = [
  "muda",
  "rfd",
  "serde_json",
+ "winit",
  "winresource",
 ]
 

apps/designcraft/Cargo.toml

@@ -24,5 +24,9 @@ winresource = "0.1"
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 rfd = { workspace = true }
 
+[target.'cfg(target_os = "linux")'.dependencies]
+# The same winit eframe uses: to pick the X11 backend (file drag-and-drop) in main.rs.
+winit = { version = "0.30", default-features = false, features = ["x11"] }
+
 [target.'cfg(target_os = "macos")'.dependencies]
 muda = { version = "0.21", default-features = false }

apps/designcraft/src/main.rs

@@ -198,6 +198,16 @@ fn main() -> eframe::Result {
     if let Some(icon) = app_icon() {
         options.viewport = options.viewport.with_icon(icon);
     }
+    // winit has no file drag-and-drop on Wayland (only on X11), so dropping images from the file
+    // manager showed a "no" cursor. Run through XWayland when it's there; DESIGNCRAFT_WAYLAND=1
+    // keeps the native Wayland backend.
+    #[cfg(target_os = "linux")]
+    if std::env::var_os("DISPLAY").is_some() && std::env::var_os("DESIGNCRAFT_WAYLAND").is_none() {
+        options.event_loop_builder = Some(Box::new(|b| {
+            use winit::platform::x11::EventLoopBuilderExtX11;
+            b.with_x11();
+        }));
+    }
     eframe::run_native(
         "DesignCraft",
         options,