feat(app): add mobile bottom navigation (#32797)

packages/app/src/context/settings.tsx

@@ -33,6 +33,7 @@ export interface Settings {
     editToolPartsExpanded: boolean
     showSessionProgressBar: boolean
     showCustomAgents: boolean
+    mobileTitlebarPosition: "top" | "bottom"
     newLayoutDesigns?: boolean
   }
   appearance: {
@@ -118,6 +119,7 @@ const defaultSettings: Settings = {
     editToolPartsExpanded: false,
     showSessionProgressBar: true,
     showCustomAgents: false,
+    mobileTitlebarPosition: "top",
   },
   appearance: {
     fontSize: 14,
@@ -248,6 +250,13 @@ export const { use: useSettings, provider: SettingsProvider } = createSimpleCont
         setShowCustomAgents(value: boolean) {
           setStore("general", "showCustomAgents", value)
         },
+        mobileTitlebarPosition: withFallback(
+          () => store.general?.mobileTitlebarPosition,
+          defaultSettings.general.mobileTitlebarPosition,
+        ),
+        setMobileTitlebarPosition(value: "top" | "bottom") {
+          setStore("general", "mobileTitlebarPosition", value)
+        },
         newLayoutDesigns,
         setNewLayoutDesigns(value: boolean) {
           setStore("general", "newLayoutDesigns", value)