Codecov integration not working for mozilla org

[freema]

Codecov reports are not showing at https://app.codecov.io/gh/mozilla/firefox-devtools-mcp.

The CI workflow uploads coverage successfully (step passes), but codecov-action with fail_ci_if_error: false silently swallows auth failures.

What's needed:

1. Install/authorize Codecov app for mozilla/firefox-devtools-mcp
2. Generate a new CODECOV_TOKEN for this repo
3. Add it as a repository secret in GitHub Settings → Secrets

The .codecov.yml config and CI workflow (ci.yml) are already set up correctly.

Note: issue tracking is officially on Bugzilla, but this is GitHub infra-specific so filing here.