Allow saving or favouriting of messages

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Feature request

Which Nextcloud Version are you currently using: (see administration page) c.nc

Is your feature request related to a problem? Please describe.
Fast moving chats (such as Engineering) have a lot of pertinent information that is easily lost when the chat moves on. Days, or even weeks later, I might want to refer to a message again, but I don't want to scroll through thousands of messages to get to the information I need. Searching might work, but if I don't remember the exact wording, I might not be able to find the message.

Unless I forward myself the message in my "Note To Self" chat, I have no way to "Put a pin in it" so to speak.

Describe the solution you'd like

A favourite / save button for messages that allows me to save a message, which will show me the complete message and will take me to the correct chat position when clicked. A tab in the sidebar could work, or a modal.

Describe alternatives you've considered
Having those messages forwarded the "Note to Self" chat - for that, the message context might be missing though, as we only forward content, not original author and timestamp, and there is no linking to the original message either.

Additional context
None.

The issue names no files, tests, or entry points. Start by mapping how message actions and message data are handled, then clarify the storage, navigation, and sidebar or modal behavior before implementation. Done should mean a user can save a message, view its complete context, and return to its original chat position.