Feat/message convenience methods

[NEFORCEO]

Message convenience methods

Add ergonomic methods to Message for common conversation actions:

• message.search(q, ...) — search messages in the current chat
• message.get_history(...) — fetch chat history
• message.get_invite_link(...) — get invite link for the chat
• message.get_conversation_members(...) — list conversation participants
• message.mark_as_important(...) — bookmark the message
• message.restore() — restore a deleted message
• message.get_by_conversation_message_id(...) — fetch by local conversation ID

Instead of:

result = await bot.messages.search(q="hello", peer_id=message.peer_id)

Now:

result = await message.search(q="hello")

FastVK method namespace properties

Add @property accessors on FastVK so type checkers resolve bot.messages, bot.users, etc. without errors:

Property	Methods
bot.messages	send, edit, delete, search, pin, unpin, ...
bot.users	get, search
bot.groups	getById, getMembers, getLongPollServer
bot.wall	get, post, getById
bot.photos	getMessagesUploadServer, saveMessagesPhoto
bot.docs	getMessagesUploadServer, save

Previously only Bot had these — FastVK users had to work around the type checker with # type: ignore or getattr.

Files changed

• fastvk/types/message.py — 7 new methods on Message
• fastvk/app.py — 6 @property accessors on FastVK
• examples/messages/all_methods.py — updated to use message.search() etc.
• docs/en/tutorial/message.md — new sections (Search, History, Invite link, Members, Bookmark)
• docs/ru/tutorial/message.md — same in Russian
• docs/en/reference/types.md — new method signatures
• docs/ru/reference/types.md — same in Russian
• docs/en/reference/fastvk.md — namespace table added
• docs/ru/reference/fastvk.md — added namespace table