When a package has a git_url but uses a non-gittag source, the
supplementary git clone was always shallow. For packages never cloned
before, a shallow clone may miss older tags that clients need.
Now: check whether the _gittag raw cache is already populated. If it is,
reuse the shallow flag (fast refresh). If it is not, force a full clone
so all tags are available from the first fetch.
The --shallow flag (global) still overrides this so operators can cap
fetch depth when needed.
Rewrites the Node.js release classification pipeline in Go. webicached
fetches upstream releases, classifies assets, and writes legacy-format
JSON caches. webid serves the HTTP API (releases, resolve, bootstrap
scripts). Git-clone packages emit git_tag and git_commit_hash from
real repo clones — no fabricated refs.
