📎 feat: Attachment Handling for v1/completions

[danny-avila]

Summary

• Added support for processing attachments in the buildPrompt method, allowing for seamless integration of image data into the conversation context.
• Refactored the prompt prefix generation to incorporate the newly augmented prompt when attachments are present.
• Removed the default date-based prompt prefix, allowing for more flexible and context-specific prompts.

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• My changes do not introduce new warnings
• I have tested the changes to ensure they work as expected