Cache completion on cursor movement

[VJHack]

To maximize server and cache utilization, it might be wise to make a FIM completion request whenever there is cursor movement. A lot of the time when we move the cursor around without typing, the server is idle. We should always be speculating the user's next action. After we receive a FIM completion response from the server, this will not be displayed until the user starts typing and it's a cache hit.

Logic:

1. User moves cursor or just opens a file
2. Make FIM completion request to llama-server
3. Cache response (don't display suggestion)

Implementing this feature would help reduce "cold start" times as prefill has already taken place.

[igardev]

Makes sense. Thank you for the idea.