Add support for LLM integration.

[missionmike]

As a user, I want to be able to perform the following steps:

1. Paste the text from a job listing into a text field in the studio dashboard.
2. Click an "Optimize and Print to PDF" option (this depends on "Print to PDF" issue)
3. Request is sent to LLM endpoint that will include the following payload (rough concept):

{
  "listingText": "...",
  "resumeData": {
    // structured resume data including bullet points.
  }
}

The prompt would instruct the LLM to only modify the bullet points and associated skills to more closely match the provided job listing text.

4. The response received from the LLM is in the same JSON-format as provided originally.
5. The response is parsed into the "Print to PDF" helper to render the structured data to PDF.