uptime metrics (yperf.com)

I've iterated YPerf since last submission with features to make LLM selection more data-driven:

- Added benchmark rankings from lmarena.ai to quantify model intelligence - Built-in cost estimator to forecast average usage expenses - Real-time uptime monitoring across providers - Side-by-side provider comparisons for identical models

The goal is to help teams make more informed decisions when choosing LLMs by providing transparency around performance, reliability and costs.