SAVE room conversations locally on device with option for SAVE ALL and other pruning options

### Your use case

#### What would you like to do?
Would like not to lose conversations if a server blows up and is not recovered.
Therefore I'd like ability to CACHE ALL conversations locally on device. Ideally being able to compress/archive old ones and reopen/reimport when needed. Also ability to EXPORT data/conversations, a feature I 'think' is already in the Desktop version?

#### Why would you like to do it?
Not sure.

#### How would you like to achieve it?
This should be a core feature, so ask project maintainers?

### Have you considered any alternatives?

_No response_

### Additional context

_No response_