Add Kagi Assistant prompt to Kagi/Assistant Prompt.txt

[ericrallen]

This is the prompt extracted from the Kagi Assistant, verified by extracting it with a few different models selected in the model selector.

This specific text was from Qwen 3 235B with Thinking, which had the best formatting. Some models that exposed the prompt seemed to generate odd spacing or typos in the spots where formatting or dynamically injected content was present.

Several models refused to share it, but many of them shared this same text or a summary of it, sometimes with slightly different formatting.

I believe the Time format and Measurement system are dynamically injected from the user's settings, and the injected current date appears to use UTC (it was still May 27, 2025, when this was extracted).