feat(telegram-chat-bot): implement AI chat bot with multi-model support

- Add NestJS service with Telegraf for Telegram bot
- Implement commands: /models, /model, /new, /convos, /history, /clear
- Create Chat API client for completions and conversations
- Support multiple AI models (local Gemma + cloud via OpenRouter)
- Sync conversations with Chat web/mobile app
- Add message splitting for long responses
- Include Dockerfile, CLAUDE.md, and setup script

Commands:
- Send text → AI responds
- /models - List available models
- /model [name] - Switch model (gemma, claude, gpt, etc.)
- /new [title] - New conversation
- /convos - List conversations
- /history - Show recent messages
- /clear - Clear context

https://claude.ai/code/session_01LwmhvhKpEsvVtY1ZKhYu6f

services/telegram-chat-bot/.env.example

@@ -0,0 +1,18 @@
+# Server
+PORT=3305
+NODE_ENV=development
+TZ=Europe/Berlin
+
+# Telegram
+TELEGRAM_BOT_TOKEN=xxx                      # Bot Token from @BotFather
+TELEGRAM_ALLOWED_USERS=                     # Optional: Comma-separated user IDs
+
+# Chat Backend API
+CHAT_API_URL=http://localhost:3002
+MANA_CORE_AUTH_URL=http://localhost:3001
+
+# Database (for telegram user links and settings)
+DATABASE_URL=postgresql://manacore:devpassword@localhost:5432/chat_bot
+
+# Default AI Model
+DEFAULT_MODEL=gemma3:4b