Cache latest message history

[ASuspiciousRat]

Problem

When the main fluxer server goes down, the entire system is unusable. Currently, this is a noticeable issue, and even after the infra is improved, will be an issue both for the main server and self hosted instances.

Proposed solution

Automatically caching the latest messages in communities you access would allow you to still be able to read the last messages before it went down. Of course you wont be able to do anything, but it'll significantly improve the inconveniences caused by a server going down.

Notes (optional)

This is extremely similar to #389 but is for a completely different situation

Checks

• I searched for existing discussions and didn't find a duplicate.

[ZackMercury]

Please rename the topic into something like

"Do not throw the user into Loading page upon connectivity issues/errors". Things don't need to be cached to not cause inconveniences. It's enough to just preserve the app state.

[ASuspiciousRat]

This suggestion is for if the app is opened during an issue. The app can't be preserved without caching if it hasn't been opened since last boot.