refactor(app): restructure settings with modular section navigation

packages/app/src/components/sidebar/sidebar-separator.tsx

@@ -0,0 +1,18 @@
+import { View } from "react-native";
+import { StyleSheet } from "react-native-unistyles";
+
+/**
+ * Edge-to-edge separator line for sidebars. Must render outside any horizontally
+ * padded container so the line runs the full sidebar width — matching the
+ * separator beneath the workspace sidebar's "New agent" header.
+ */
+export function SidebarSeparator() {
+  return <View style={styles.line} />;
+}
+
+const styles = StyleSheet.create((theme) => ({
+  line: {
+    borderBottomWidth: 1,
+    borderBottomColor: theme.colors.border,
+  },
+}));