Stream LLM response when editing apps

[benjreinhart]

Follow ups:

• Change creation flow immediately redirect to created app and use edit flow to get streaming support
• Stream partial plan description markdown text
• Break response into more granular pieces we can display on client for more responsiveness

[nichochar]

LGTM. Given how this works, we should be able to populate the DiffBox temporarily with "updating ${filename}..."

Although we need to be careful to not make that clickable otherwise if users click on the file we'll interrupt the request

[nichochar]

I realized that we could also push the file streams another way:

• we could be pushing them through the websocket "file:updated"
• this would mean they update real time
• at the end of the request, we could still send the total diff plan like we did before
  I think this might work well, but might present issues based on the ordering of the LLM's response tags

[benjreinhart]

Yes for sure, we can improve this a lot beyond this first pass.