fix: handle MessageReplyStoryHeader without reply_to_msg_id attribute

[akhromovRT]

Summary

Message.reply_to in Telethon can be either MessageReplyHeader (when the
message replies to another regular message) or MessageReplyStoryHeader
(when it replies to a story). Only the former carries reply_to_msg_id;
the latter has story_id + peer instead.

Before this fix, get_history() and list_messages() crashed with
AttributeError as soon as the requested range contained a
reply-to-story message:

File "telegram_mcp/tools/messages.py", line 1080, in get_history
    if msg.reply_to and msg.reply_to.reply_to_msg_id:
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'MessageReplyStoryHeader' object has no attribute
'reply_to_msg_id'

This made any sufficiently large history fetch unreliable for users whose
chats include story-reply messages — symptom is GEN-ERR-971 in MCP logs.

Fix

Use getattr(msg.reply_to, "reply_to_msg_id", None) to safely probe for
the attribute on whichever reply-header class is attached. Behavior for
ordinary MessageReplyHeader is unchanged.

Test plan

• Manually reproduced the crash with get_history(chat_id, limit=200)
  on a chat containing a reply-to-story message
• After patch — same call returns 200 messages successfully
• Replies to regular messages still populate reply_to field in the
  output (verified on a chat with both reply types)