Complete the documentation suite with:
- Deep-dive metrics reference (LCP, FCP, CLS, TBT, TTFB)
- Detailed testing engines comparison (Sitespeed vs PSI)
- Why TBT is the killer metric for rds.ink
- How to fix each metric using Hummingbird
- Score differences and when to use each engine
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
