Removes the Linux guard (was: exit 1 with apt suggestion).
Adds pkg_install branch for Linux: extracts bare fish binary from
fish-VERSION-linux-ARCH.tar.xz into ~/.local/opt/fish-vVERSION/bin/.
Adds _linux_post_install() with chsh instructions.
macOS: installs fish*.app to /Applications/fish.app (covers v3 fish.app
and v4 fish-VERSION.app); pkg_link symlinks Contents/MacOS/fish.
OS detection via uname -s at top level; functions have no OS guards.
pkg_link avoids calling webi_link (would recurse since webi_link calls
pkg_link when defined).
Replaces [ with test throughout per POSIX shell conventions.
Co-authored-by: AJ ONeal <aj@therootcompany.com>
Stacked on the modifications PR. Now that no live code path references
the per-package fetchers, the shared HTTP/parsing helpers, the
in-process normalizer, or the example template, delete them. Pure
deletion — no behavior change.
- ~93 per-package <pkg>/releases.js fetcher modules.
- _common/{brew,fetcher,git-tag,gitea,github,github-source,
githubish,githubish-source}.js shared HTTP/parsing helpers.
- _webi/normalize.js in-process normalization layer (cache files
arrive normalized from webicached).
- _example/releases.js fetcher template for new packages.
The Go cache daemon (webicached) is now the sole producer of release
metadata; the Node process never makes an upstream request.
