Memory Optimizations for Large Sessions

[chezsmithy]

During longer sessions where the compaction feature is utilized, the chat history can become quite large in the memory / DOM. This can cause the extension to become sluggish and in extreme cases can cause certain components to render incorrectly.

I'd like to recommend a couple of approachs to managing the chat history in memory post compaction:

1. Prune everything before the compaction and update the session stored on disk to reflect this. (simple)
2. Update session management so that when compaction occurs the messages before the latest compaction are stored in the session on disk but they are removed from memory. Only bring them back into memory if the session is reloaded or perhaps add a UX element to allow a user to reload messages before the latest compaction, but prune them again as soon as the session is resumed.