Adds group chat support and brevity rules

[magicxor]

Extends the bot's functionality to handle group chats, introducing specific rules for brevity in responses within group contexts.

This change ensures the bot provides concise answers by default in group chats, while still allowing users to request more detailed information when needed.

It also addresses an issue where group chats were not handled differently, leading to overly verbose responses.

[Copilot]

Pull Request Overview

This PR extends the Telegram bot's functionality to handle group chats differently from private chats by introducing brevity rules. The main purpose is to ensure the bot provides concise responses by default in group chat contexts while maintaining the ability for users to request detailed information when needed.

Key changes:

• Added group chat detection logic throughout the message handling pipeline
• Introduced group-specific system prompt rules emphasizing brevity
• Modified method signatures to pass group chat context through the entire call chain

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
Pacos/Services/TelegramBotService.cs	Detects group chat type and passes it to mention handler
Pacos/Services/GenerativeAi/ChatService.cs	Modifies system prompt generation to include group chat rules
Pacos/Services/ChatCommandHandlers/MentionHandler.cs	Updates method signatures to propagate group chat context
Pacos/Constants/Const.cs	Adds group chat-specific brevity rules and updates existing prompt

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