`--offline` version resolution could only see cached node binaries:
`nvm_ls_cached` listed `.cache/bin` with a `node-` prefix filter,
so cached source tarballs, and everything io.js, could never resolve offline.
List both cache kinds, for both flavors,
and update the pinned test expectations to match.
The test was born without its executable bit,
and urchin silently skips non-executable files, so it has never run.
Also pin what `nvm_ls_cached` can currently see:
only bin-cached node artifacts - bin-cached io.js, and src-cached anything,
are invisible to it, and thus to `--offline` version resolution.
Add `--offline` flag to `nvm install` that resolves versions using only locally installed versions and cached downloads. No network calls are made.
New helper functions `nvm_ls_cached` and `nvm_offline_version` scan `$NVM_DIR/.cache/bin/` for previously downloaded tarballs.
In offline mode, `nvm_download_artifact` returns cached tarballs directly without checksum verification or download attempts.
The curl/wget requirement is skipped when `--offline` is set.
Supports `--lts` via locally stored LTS alias files.