perf: strip load function for supporting heavy sessions

[sagarsrc]

Scope

backend

What's slow?

• when the conversation becomes really long >100 turns there is significant downgrade in the experience
• additionally chats with attached images are in base64 i have a hunch this might be slowing it down

Proposed fix

• Can we load stripped jsonl instead of entire jsonl?
• Can we have some pointer to attached image like [image 1] in that jsonl
• Can we have optimized preprocessor which runs on every update in the session
• see how frontend can be optimized