Add background update checks with configurable interval

src/window.rs

@@ -961,6 +961,37 @@ impl DriftwoodWindow {
             });
         }
 
+        // Scheduled background update check
+        let settings_upd = self.settings().clone();
+        if settings_upd.boolean("auto-check-updates") {
+            let last_check = settings_upd.string("last-update-check").to_string();
+            let interval_hours = settings_upd.int("update-check-interval-hours") as i64;
+            let should_check = if last_check.is_empty() {
+                true
+            } else if let Ok(last) = chrono::NaiveDateTime::parse_from_str(&last_check, "%Y-%m-%d %H:%M:%S") {
+                let now = chrono::Utc::now().naive_utc();
+                let elapsed = now.signed_duration_since(last);
+                elapsed.num_hours() >= interval_hours
+            } else {
+                true
+            };
+            if should_check {
+                let settings_save = settings_upd.clone();
+                glib::spawn_future_local(async move {
+                    let result = gio::spawn_blocking(move || {
+                        let bg_db = Database::open().expect("DB open failed");
+                        update_dialog::batch_check_updates(&bg_db)
+                    })
+                    .await;
+                    if let Ok(count) = result {
+                        log::info!("Background update check: {} updates available", count);
+                    }
+                    let now = chrono::Utc::now().format("%Y-%m-%d %H:%M:%S").to_string();
+                    settings_save.set_string("last-update-check", &now).ok();
+                });
+            }
+        }
+
         // Check for orphaned desktop entries in the background
         let toast_overlay = self.imp().toast_overlay.get().unwrap().clone();
         glib::spawn_future_local(async move {