Agent Skills: ring:researching-features

Researching the product/feature in depth before any planning document is written: the product itself, technical approach, third-party integrations, prior art, and existing codebase grounding (file:line refs) via parallel repo/web/docs agents using firecrawl and exa. Gate 0 of ring:using-pm-team (both tracks); runs before ring:writing-prds. Use before pre-dev planning a new feature or modification. Skip for trivial changes or when a recent research.md already exists.