How I configure Codecov for path-filtered monorepo CI — the .codecov.yml file: per-flag carryforward (so packages that didn't run this push don't report as dropped coverage), project/patch status targets, per-flag target overrides, ignore paths, and the PR comment layout. Complements the upload step in the ci skill. Use when adding/tuning .codecov.yml, fixing red coverage on untouched packages, or wiring a new sub-package's flag.
