feat(telegram): native dialogs for confirms and deep-link notices

Inside the Mini App, route the destructive confirmations (resign, block, unfriend)
through Telegram's native showConfirm, and present the deep-link info modals (stale
invite, welcome-on-redeem) as a native showPopup whose button opens the bot chat.
Outside Telegram, or on a client predating the dialogs, the existing in-app Modal is
used unchanged; offline also keeps the modal so the action retains its disabled state.

Adds showConfirm/showPopup wrappers to telegram.ts and a pure popup-params builder
(nativedialogs.ts) with unit tests; the deep-link modal components choose native vs
in-app via an effect gated on insideTelegram + dialog availability.

ui/src/lib/telegram.test.ts

@@ -10,6 +10,9 @@ import {
   telegramThemeParams,
   telegramSafeAreaInset,
   telegramShowSettingsButton,
+  telegramDialogsAvailable,
+  telegramShowConfirm,
+  telegramShowPopup,
 } from './telegram';
 
 function stubWebApp(initData: string, startParam?: string) {
@@ -96,6 +99,38 @@ describe('telegramShowSettingsButton', () => {
   });
 });
 
+describe('native dialogs', () => {
+  afterEach(() => vi.unstubAllGlobals());
+
+  it('telegramDialogsAvailable reflects showPopup presence', () => {
+    expect(telegramDialogsAvailable()).toBe(false);
+    vi.stubGlobal('window', { Telegram: { WebApp: { showPopup: () => {} } } });
+    expect(telegramDialogsAvailable()).toBe(true);
+  });
+
+  it('telegramShowConfirm resolves the user choice inside Telegram', async () => {
+    vi.stubGlobal('window', {
+      Telegram: { WebApp: { showConfirm: (_m: string, cb: (ok: boolean) => void) => cb(true) } },
+    });
+    await expect(telegramShowConfirm('Sure?')).resolves.toBe(true);
+  });
+
+  it('telegramShowConfirm resolves false without the SDK dialog', async () => {
+    await expect(telegramShowConfirm('Sure?')).resolves.toBe(false);
+  });
+
+  it('telegramShowPopup resolves the pressed button id', async () => {
+    vi.stubGlobal('window', {
+      Telegram: { WebApp: { showPopup: (_p: unknown, cb: (id: string) => void) => cb('bot') } },
+    });
+    await expect(telegramShowPopup({ message: 'Hi' })).resolves.toBe('bot');
+  });
+
+  it('telegramShowPopup resolves null without the SDK', async () => {
+    await expect(telegramShowPopup({ message: 'Hi' })).resolves.toBeNull();
+  });
+});
+
 describe('routeExternalLinkInTelegram', () => {
   afterEach(() => vi.unstubAllGlobals());