New fetcher packages:
- golang: golang.org/dl/?mode=json&include=all
- zigdist: ziglang.org/download/index.json
- flutterdist: Google Storage per-OS release indexes
- iterm2dist: scrapes iterm2.com/downloads.html
- hashicorp: releases.hashicorp.com/{product}/index.json
- juliadist: julialang-s3.julialang.org/bin/versions.json
Each follows the same iter.Seq2 pattern as the existing nodedist/github
fetchers. Added releases.conf files for all six packages and wired them
into cmd/fetchraw.
Fixed latest-version detection for sources that return unordered data
(hashicorp, zigdist, juliadist) by comparing all versions with lexver
instead of taking the first stable one found.
