feat(io): delete .sv$ autosave files on clean save/exit (#205)

The .sv$ recovery copies only need to survive a crash, so they are removed on
a clean save (Save and Save-As both delete the file's .sv$ after writing) and
on a clean exit — a new exit_app() runs cleanup_autosaves over every open tab
before quitting, and all iced::exit() paths now funnel through it. A leftover
.sv$ therefore signals an unclean shutdown, i.e. something to recover.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/app/commands/fileops.rs

@@ -211,7 +211,7 @@ impl OpenCADStudio {
                 if let Some(id) = self.main_window {
                     return Some(Task::done(Message::WindowCloseRequested(id)));
                 }
-                return Some(iced::exit());
+                return Some(self.exit_app());
             }
 
             // ── Frame-budget HUD (Phase 5.3) ───────────────────────────────

src/app/update/dialog.rs

@@ -186,7 +186,7 @@ pub(super) fn on_ribbon_tool_click(&mut self, tool_id: String, event: ModuleEven
                             self.pending_close = Some(crate::app::PendingClose::Quit);
                         } else {
                             let close_win = self.close_unsaved_dialog_window();
-                            return Task::batch(vec![close_win, iced::exit()]);
+                            return Task::batch(vec![close_win, self.exit_app()]);
                         }
                     }
                     None => {}
@@ -252,7 +252,7 @@ pub(super) fn on_ribbon_tool_click(&mut self, tool_id: String, event: ModuleEven
                             self.pending_close = Some(crate::app::PendingClose::Quit);
                         } else {
                             let close_win = self.close_unsaved_dialog_window();
-                            return Task::batch(vec![close_win, iced::exit()]);
+                            return Task::batch(vec![close_win, self.exit_app()]);
                         }
                     }
                     None => {}
@@ -299,7 +299,7 @@ pub(super) fn on_ribbon_tool_click(&mut self, tool_id: String, event: ModuleEven
                                     self.pending_close = Some(crate::app::PendingClose::Quit);
                                     return self.open_unsaved_dialog_window();
                                 } else {
-                                    return iced::exit();
+                                    return self.exit_app();
                                 }
                             }
                             Err(e) => {

src/app/update/file.rs

@@ -550,6 +550,8 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                             self.command_line
                                 .push_output(&format!("Saved: {}", path.display()));
                             self.tabs[i].dirty = false;
+                            // A clean save supersedes any autosave recovery copy.
+                            let _ = std::fs::remove_file(path.with_extension("sv$"));
                         }
                         Err(e) => self.command_line.push_error(&format!("Save failed: {e}")),
                     }
@@ -615,6 +617,8 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
                                 .push_output(&format!("Saved: {}", path.display()));
                             self.tabs[i].current_path = Some(path.clone());
                             self.tabs[i].dirty = false;
+                            // A clean save supersedes any autosave recovery copy.
+                            let _ = std::fs::remove_file(path.with_extension("sv$"));
                             if self.save_dialog_for_unsaved {
                                 let next = self.update(Message::UnsavedPickedSavePath(Some(path)));
                                 return Task::batch([close, next]);
@@ -712,6 +716,23 @@ pub(super) fn on_open_file(&mut self) -> Task<Message> {
         Task::none()
     }
 
+    /// Delete the `.sv$` autosave recovery files for all open drawings. They
+    /// exist only to survive a crash, so a clean save or exit removes them.
+    pub(in crate::app) fn cleanup_autosaves(&self) {
+        #[cfg(not(target_arch = "wasm32"))]
+        for t in &self.tabs {
+            if let Some(path) = &t.current_path {
+                let _ = std::fs::remove_file(path.with_extension("sv$"));
+            }
+        }
+    }
+
+    /// Remove the autosave recovery files, then quit the application.
+    pub(in crate::app) fn exit_app(&self) -> Task<Message> {
+        self.cleanup_autosaves();
+        iced::exit()
+    }
+
     pub(super) fn on_page_setup_commit(&mut self) -> Task<Message> {
                 let i = self.active_tab;
                 let layout_name = self.tabs[i].scene.current_layout.clone();

src/app/update/mod.rs

@@ -809,7 +809,7 @@ impl OpenCADStudio {
                         self.pending_close = Some(super::PendingClose::Quit);
                         return self.open_unsaved_dialog_window();
                     }
-                    return iced::exit();
+                    return self.exit_app();
                 }
                 Task::none()
             }
@@ -818,7 +818,7 @@ impl OpenCADStudio {
                 // Only the main window exists now; all dialogs are in-canvas
                 // modals (Plan B). Closing it exits.
                 if self.main_window == Some(id) {
-                    return iced::exit();
+                    return self.exit_app();
                 }
                 Task::none()
             }