Initial commit: Telegram bot with Cloudflare Workers

- OpenAI GPT-4o-mini with Function Calling
- Cloudflare D1 for user profiles and message buffer
- Sliding window (3 summaries max) for infinite context
- Tools: weather, search, time, calculator
- Workers AI fallback support
- Webhook security with rate limiting

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/types.ts

@@ -0,0 +1,68 @@
+export interface Env {
+  DB: D1Database;
+  AI: Ai;
+  BOT_TOKEN: string;
+  WEBHOOK_SECRET: string;
+  SUMMARY_THRESHOLD?: string;
+  MAX_SUMMARIES_PER_USER?: string;
+  N8N_WEBHOOK_URL?: string;
+  OPENAI_API_KEY?: string;
+}
+
+export interface IntentAnalysis {
+  action: 'chat' | 'n8n';
+  type?: string;
+  confidence: number;
+}
+
+export interface N8nResponse {
+  reply?: string;
+  error?: string;
+}
+
+export interface TelegramUpdate {
+  update_id: number;
+  message?: TelegramMessage;
+}
+
+export interface TelegramMessage {
+  message_id: number;
+  from: TelegramUser;
+  chat: TelegramChat;
+  date: number;
+  text?: string;
+}
+
+export interface TelegramUser {
+  id: number;
+  is_bot: boolean;
+  first_name: string;
+  last_name?: string;
+  username?: string;
+}
+
+export interface TelegramChat {
+  id: number;
+  type: string;
+}
+
+export interface BufferedMessage {
+  id: number;
+  role: 'user' | 'bot';
+  message: string;
+  created_at: string;
+}
+
+export interface Summary {
+  id: number;
+  generation: number;
+  summary: string;
+  message_count: number;
+  created_at: string;
+}
+
+export interface ConversationContext {
+  previousSummary: Summary | null;
+  recentMessages: BufferedMessage[];
+  totalMessages: number;
+}