App: a lost graphics device tells the user why the window closes and where the recovery copy is (#591)

Ported from #673: a native error dialog names the auto-saved recovery copy before the window
closes; agent runs through the control channel skip it. The UI calls Hooks::device_lost once.

Co-Authored-By: Dennis M. Francis <[email protected]>
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01QiAJeFttZp83Fh7YuzAR5f

apps/effectcraft/src/main.rs

@@ -210,6 +210,22 @@ fn main() -> eframe::Result {
             app.hooks.pick_save = Some(Box::new(|name: &str| {
                 rfd::FileDialog::new().add_filter("EffectCraft Project", &["ecproj"]).set_file_name(name).save_file().map(|p| p.to_string_lossy().to_string())
             }));
+            // The window closes after a lost graphics device (#591); say why, unless an agent drives
+            // the app through the control channel.
+            if control_port.is_none() {
+                app.hooks.device_lost = Some(Box::new(|saved: Option<Result<String, String>>| {
+                    let saved = match saved {
+                        Some(Ok(path)) => format!("\n\nYour unsaved changes were saved to:\n{path}\n\nReopen EffectCraft to recover them."),
+                        Some(Err(e)) => format!("\n\nYour unsaved changes could not be saved ({e})."),
+                        None => String::new(),
+                    };
+                    rfd::MessageDialog::new()
+                        .set_level(rfd::MessageLevel::Error)
+                        .set_title("EffectCraft: graphics device lost")
+                        .set_description(format!("The graphics driver stopped responding, so EffectCraft has to close.{saved}"))
+                        .show();
+                }));
+            }
             app.hooks.pick_open_project = Some(Box::new(|| {
                 rfd::FileDialog::new().add_filter("EffectCraft Project", &["ecproj", "ecprojx"]).pick_file().map(|p| p.to_string_lossy().to_string())
             }));