feat(app): add chat outline navigation (#2792)

* feat(app): add chat outline navigation

Long agent sessions need prompt navigation without coupling viewport movement to disposable server windows. Keep fetched timeline pages in client state so repeated jumps stay local, and settle prompt jumps against virtualized row measurement changes.

* fix(app): preserve chat outline timeline coverage

* fix(app): reconcile outline window submissions

* fix(app): harden outline timeline navigation

packages/app/src/screens/settings/appearance/appearance-section.tsx

@@ -212,6 +212,30 @@ function AutoExpandReasoningRow({ value, onChange }: AutoExpandReasoningRowProps
   );
 }
 
+interface ChatOutlineRowProps {
+  value: boolean;
+  onChange: (value: boolean) => void;
+}
+
+function ChatOutlineRow({ value, onChange }: ChatOutlineRowProps) {
+  const { t } = useTranslation();
+  return (
+    <View style={[settingsStyles.row, settingsStyles.rowBorder]}>
+      <View style={settingsStyles.rowContent}>
+        <Text style={settingsStyles.rowTitle}>{t("settings.appearance.chatOutline.title")}</Text>
+        <Text style={settingsStyles.rowHint}>
+          {t("settings.appearance.chatOutline.description")}
+        </Text>
+      </View>
+      <Switch
+        value={value}
+        onValueChange={onChange}
+        accessibilityLabel={t("settings.appearance.chatOutline.title")}
+      />
+    </View>
+  );
+}
+
 const TOOL_CALL_DETAIL_LEVELS: readonly AppSettings["toolCallDetailLevel"][] = [
   "detailed",
   "overview",
@@ -503,6 +527,13 @@ export function AppearanceSection() {
     [updateSettings],
   );
 
+  const handleChatOutlineChange = useCallback(
+    (chatOutlineEnabled: boolean) => {
+      void updateSettings({ chatOutlineEnabled });
+    },
+    [updateSettings],
+  );
+
   const commitUiFontFamily = useCallback(
     (value: string) => {
       const sanitized = sanitizeFontFamily(value);
@@ -593,6 +624,12 @@ export function AppearanceSection() {
             value={settings.toolCallDetailLevel}
             onChange={handleToolCallDetailLevelChange}
           />
+          {!isNative ? (
+            <ChatOutlineRow
+              value={settings.chatOutlineEnabled}
+              onChange={handleChatOutlineChange}
+            />
+          ) : null}
         </View>
       </SettingsSection>
       <SettingsSection title={t("settings.appearance.fonts.title")}>