Better configuration for quick action prompts

[StructByLightning]

Validations

• [X] I believe this is a way to improve. I'll try to join the Continue Discord for questions
• [X] I'm not able to find an open issue that requests the same enhancement

Problem

Quick Actions (experimental.quickActions) currently have a prompt field that gets inserted into a hardcoded template. There also appears to be no mechanism to set the system prompt.

While this is fine as a default, it's frustrating as a power user with prompt engineering skills. It would be nice if I could define my own prompt template, including the system message and prefilled assistant response. (Prefilling the response makes it much more likely that the AI will respond in the correct way -- for example, you can prefill with the opening ticks of a code block to push it to respond with a codeblock.)

Solution

I propose breaking the prompt field into three fields:

{
  "systemMessage" //system message sent to the model
  "prompt" //user message sent to the model
  "prefilledResponse" //prefilled response sent to the model