### Fixed

- `actions/docs-sync` fetches the doctrine mirror from the forge named by
  `GITHUB_SERVER_URL` instead of a hard-coded `github.com` (#201).

- The same pin ref names a different tree on each forge, so a consumer's mirror
  was verified against a tree it never pinned — and with HTTP 200, so `--check`
  reported drift that could not be fixed (#201).

- A fetch that cannot name its forge now refuses instead of guessing: no
  `GITHUB_SERVER_URL` and no `--source` exits naming the variable, having
  reached for no network (#201).

- A failed fetch names the URL it actually tried, and asks whether the ref
  exists on that forge rather than in the abstract (#201).

### Added

- `test/docs-sync.test.sh` drives the fetch path, which had no coverage at all:
  every existing row passes `--source`, which overrides the fetch entirely
  (#201).

- A stubbed `curl` records the requested URL and serves a tarball, so which
  forge a pin resolves against is a tested decision rather than plumbing (#201).