feat(telegram): native SettingsButton opens our Settings screen

Inside the Mini App, reveal Telegram's native Settings button (Bot API 7.0)
and route its taps to the Settings screen — the standard Mini App affordance.
The in-app gear entry stays the primary path (two entry points by design).
No-op outside Telegram or on a client predating the button.

ui/src/lib/app.svelte.ts

@@ -22,6 +22,7 @@ import {
   telegramContentSafeAreaTop,
   telegramSafeAreaInset,
   telegramDisableVerticalSwipes,
+  telegramShowSettingsButton,
   telegramHaptic,
   telegramLaunch,
   type TelegramLaunch,
@@ -647,6 +648,9 @@ export async function bootstrap(): Promise<void> {
     telegramOnEvent('fullscreenChanged', syncTelegramSafeArea);
     // Re-apply the theme live when the user switches Telegram's light/dark mode while the app is open.
     telegramOnEvent('themeChanged', () => syncTelegramTheme());
+    // Telegram's native Settings button (Bot API 7.0) opens our Settings screen; the in-app gear
+    // entry stays the primary path. No-op on clients predating the button.
+    telegramShowSettingsButton(() => navigate('/settings'));
     await bootTelegram(launch);
     app.ready = true;
     return;

ui/src/lib/telegram.test.ts

@@ -9,6 +9,7 @@ import {
   telegramOpenExternalLink,
   telegramThemeParams,
   telegramSafeAreaInset,
+  telegramShowSettingsButton,
 } from './telegram';
 
 function stubWebApp(initData: string, startParam?: string) {
@@ -77,6 +78,24 @@ describe('telegramOpenExternalLink', () => {
   });
 });
 
+describe('telegramShowSettingsButton', () => {
+  afterEach(() => vi.unstubAllGlobals());
+
+  it('shows the native Settings button and wires its click inside Telegram', () => {
+    const onClick = vi.fn();
+    const show = vi.fn();
+    const handler = vi.fn();
+    vi.stubGlobal('window', { Telegram: { WebApp: { SettingsButton: { onClick, show } } } });
+    telegramShowSettingsButton(handler);
+    expect(onClick).toHaveBeenCalledWith(handler);
+    expect(show).toHaveBeenCalled();
+  });
+
+  it('is a no-op without the SDK button (older client / outside Telegram)', () => {
+    expect(() => telegramShowSettingsButton(() => {})).not.toThrow();
+  });
+});
+
 describe('routeExternalLinkInTelegram', () => {
   afterEach(() => vi.unstubAllGlobals());
 

ui/src/lib/telegram.ts

@@ -41,6 +41,12 @@ interface TelegramWebApp {
     onClick?: (cb: () => void) => void;
     offClick?: (cb: () => void) => void;
   };
+  SettingsButton?: {
+    show?: () => void;
+    hide?: () => void;
+    onClick?: (cb: () => void) => void;
+    offClick?: (cb: () => void) => void;
+  };
 }
 
 function webApp(): TelegramWebApp | undefined {
@@ -293,6 +299,19 @@ export function telegramDisableVerticalSwipes(): void {
   webApp()?.disableVerticalSwipes?.();
 }
 
+/**
+ * telegramShowSettingsButton reveals Telegram's native Settings button (in the Mini App's ⋮ menu,
+ * Bot API 7.0) and routes its taps to handler. A no-op outside Telegram or on a client predating
+ * the button, so the app's own in-app settings entry stays the primary path. The app registers it
+ * once per launch (Telegram hides the button when the Mini App closes), so there is no offClick.
+ */
+export function telegramShowSettingsButton(handler: () => void): void {
+  const b = webApp()?.SettingsButton;
+  if (!b?.show) return;
+  b.onClick?.(handler);
+  b.show();
+}
+
 /** Haptic is the set of feedbacks the app triggers. */
 export type Haptic = 'select' | 'success' | 'error' | 'warning' | 'light' | 'medium' | 'heavy';