Audit documentation gaps across the Phoenix repo by analyzing recent commits to main (default: last 7 days). Use this skill whenever the user asks to find undocumented features, identify docs gaps, audit what shipped without docs, check which recent changes need documentation, review stale docs against current code, or mentions "documentation debt", "doc coverage", "undocumented APIs", or "what's missing from /docs". Also trigger on requests like "what from last week needs docs", "find stale READMEs", or "check docstring coverage for recent changes". Covers /docs (Mintlify), package READMEs, package-level built-in docs (Sphinx, TypeDoc), Python docstrings, TSDoc, and code comments.