[Bug] Implement Loading of Previous Chats

[KRYSTALM7]

Previous chat sessions are not being loaded properly (or not loading at all).
Expected Behavior:
Ability to fetch and display chat history from local storage or backend.
Display session titles or timestamps for easy identification.

⚠️ Note:

• For documentation issues, please open an issue in Dijkstra-Edu/docs.
• For discussions or proposals, please create a GitHub Discussion.

[JRS296]

Need to add feature such that unless user configures backend storage for their chats (either MongoDB or Supabase) it will not be stored.