feat(telegram): integrate Telegram bot for notifications and add related models

apps/frontend/src/lib/api.ts

@@ -319,3 +319,23 @@ export function importPeriodicExpenses(file: File): Promise<ImportResult> {
     return r.json();
   });
 }
+
+// Telegram
+
+export type TelegramStatus = {
+  botUsername: string | null;
+  connected: boolean;
+};
+
+export type TelegramCode = {
+  code: string;
+  botUsername: string | null;
+};
+
+export function getTelegramStatus(): Promise<TelegramStatus> {
+  return fetcher<TelegramStatus>("/api/telegram/status");
+}
+
+export function generateTelegramCode(): Promise<TelegramCode> {
+  return mutator<TelegramCode>("/api/telegram/code", "POST");
+}