window: only mark articles as read when navigating away

Previously the sidebar immediately showed an article as read the
moment it was selected, while the server was only notified when
the user moved to the next article.  Align the two: mark the
previous article as read in both the sidebar and on the server
at the same time, when the user navigates away from it.

src/window.rs

@@ -137,6 +137,7 @@ pub mod imp {
             self.setup_capture_keys();
             self.restore_from_cache();
             self.auto_login();
+            self.web_view.grab_focus();
         }
     }
 
@@ -205,6 +206,8 @@ pub mod imp {
         fn setup_list(&self) {
             let store = gio::ListStore::new::<ArticleObject>();
             let selection = gtk4::SingleSelection::new(Some(store.clone()));
+            selection.set_autoselect(false);
+            selection.set_can_unselect(true);
             *self.article_store.borrow_mut() = Some(store);
 
             let factory = gtk4::SignalListItemFactory::new();
@@ -243,10 +246,12 @@ pub mod imp {
         }
 
         fn on_article_selected(&self, obj: ArticleObject) {
-            // Mark previous article as read (unless guard is set)
+            // Mark the previous article as read — both on the server and in the
+            // sidebar — now that the user has navigated away from it.
             if !*self.mark_unread_guard.borrow() {
                 if let Some(prev_id) = self.current_article_id.borrow().clone() {
                     if prev_id != obj.article().id {
+                        self.mark_read_in_list(&prev_id);
                         self.bg_mark_read(prev_id);
                     }
                 }
@@ -254,13 +259,30 @@ pub mod imp {
             *self.mark_unread_guard.borrow_mut() = false;
 
             let article = obj.article().clone();
+            let same_article = self.current_article_id.borrow().as_deref() == Some(&*article.id);
             *self.current_article_id.borrow_mut() = Some(article.id.clone());
 
             self.article_menu_button.set_visible(true);
 
-            // Load in webview
-            self.load_article_in_webview(&article);
-            obj.set_unread(false);
+            // Skip WebView reload when re-selecting the same article (e.g. after
+            // a server refresh) so the user's scroll position is preserved.
+            if !same_article {
+                self.load_article_in_webview(&article);
+            }
+        }
+
+        /// Mark an article as read in the sidebar list (UI only).
+        fn mark_read_in_list(&self, article_id: &str) {
+            if let Some(store) = self.article_store.borrow().as_ref() {
+                for i in 0..store.n_items() {
+                    if let Some(obj) = store.item(i).and_downcast::<ArticleObject>() {
+                        if obj.article().id == article_id {
+                            obj.set_unread(false);
+                            break;
+                        }
+                    }
+                }
+            }
         }
 
         fn reload_current_article(&self) {
@@ -714,39 +736,64 @@ pub mod imp {
                                 store.append(&ArticleObject::new(a.clone()));
                             }
 
-                            // Save cache and clean up unreferenced images.
-                            let sel_id = saved_id.as_deref().unwrap_or("");
-                            crate::cache::save(&articles, sel_id);
                             crate::image_cache::cleanup(&articles);
 
-                            if store.n_items() == 0 {
+                            let n = store.n_items();
+                            if n == 0 {
                                 imp.sidebar_content.set_visible_child_name("empty");
                                 *imp.current_article_id.borrow_mut() = None;
                                 imp.article_menu_button.set_visible(false);
                                 imp.content_stack.set_visible_child_name("empty");
+                                crate::cache::save(&articles, "");
                             } else {
-                                // Try to re-select the same article; fall back to first.
-                                let mut select_idx = 0u32;
-                                if let Some(ref id) = saved_id {
-                                    for i in 0..store.n_items() {
-                                        if store.item(i).and_downcast::<ArticleObject>()
+                                // Try to re-select the same article the user was reading.
+                                let found_idx = saved_id.as_ref().and_then(|id| {
+                                    (0..n).find(|&i| {
+                                        store.item(i).and_downcast::<ArticleObject>()
                                             .map(|o| o.article().id == *id)
                                             .unwrap_or(false)
-                                        {
-                                            select_idx = i;
-                                            break;
-                                        }
-                                    }
+                                    })
+                                });
+
+                                if let Some(idx) = found_idx {
+                                    // Article still unread — re-select it without
+                                    // reloading the WebView (preserves scroll position).
+                                    *imp.mark_unread_guard.borrow_mut() = true;
+                                    sel.set_selected(idx);
+                                    imp.article_list_view.scroll_to(
+                                        idx,
+                                        gtk4::ListScrollFlags::SELECT,
+                                        None,
+                                    );
+                                    crate::cache::save(&articles,
+                                        saved_id.as_deref().unwrap_or(""));
+                                } else if saved_id.is_some() {
+                                    // Article was read elsewhere — keep it in the
+                                    // WebView so the user can finish reading but
+                                    // leave the sidebar list unselected.
+                                    crate::cache::save(&articles, "");
+                                } else {
+                                    // No previous article (first load) — select the
+                                    // first article.
+                                    sel.set_selected(0);
+                                    imp.article_list_view.scroll_to(
+                                        0,
+                                        gtk4::ListScrollFlags::SELECT,
+                                        None,
+                                    );
+                                    crate::cache::save(&articles, "");
                                 }
-                                *imp.mark_unread_guard.borrow_mut() = true;
-                                sel.set_selected(select_idx);
-                                imp.article_list_view.scroll_to(
-                                    select_idx,
-                                    gtk4::ListScrollFlags::SELECT,
-                                    None,
-                                );
                                 imp.sidebar_content.set_visible_child_name("list");
                             }
+
+                            // Always notify the user that the fetch finished.
+                            let msg = if n == 1 {
+                                String::from("1 unread article")
+                            } else {
+                                format!("{n} unread articles")
+                            };
+                            let toast = libadwaita::Toast::new(&msg);
+                            imp.toast_overlay.add_toast(toast);
                         }
                         Err(e) => {
                             // If we already have cached articles, just show a toast.
@@ -845,7 +892,10 @@ pub mod imp {
             let n = sel.n_items();
             if n == 0 { return }
             let current = sel.selected();
-            let next = if delta > 0 {
+            let next = if current == gtk4::INVALID_LIST_POSITION {
+                // Nothing selected — pick the first or last article.
+                if delta > 0 { 0 } else { n - 1 }
+            } else if delta > 0 {
                 (current + 1).min(n - 1)
             } else {
                 current.saturating_sub(1)