Archive transition breaks install.sh/install.ps1 for every currently published release

[alpCaner]

Found while reviewing

PR #352, feat/v06-batch at 1cab240df85d5896c5390697c069720ff2bb24d3.

This is a regression introduced by #349's --onedir archive transition. Both installers now unconditionally request the new archive shape:

• install.sh: tan-<triple>.tar.gz
• install.ps1: tan-<triple>.zip

No currently published release has those assets. v0.4.1 is the current stable/latest release and publishes raw binaries; the published v0.5.0-rc4 also still uses the raw onefile asset.

Reproduction

sh install.sh --version v0.4.1 --dir /tmp/tan-v041 --no-modify-path
# GET .../v0.4.1/tan-x86_64-unknown-linux-gnu.tar.gz -> 404

sh install.sh --version v0.5.0-rc4 --dir /tmp/tan-v050rc4 --no-modify-path
# GET .../v0.5.0-rc4/tan-x86_64-unknown-linux-gnu.tar.gz -> 404

The branch's getting-started workflow fails in the default latest path for the same reason: latest resolves to v0.4.1, then the installer requests a nonexistent archive.

The comments/docs currently say archives start at v0.5.0-rc4, which conflicts with the assets actually published for that tag.

Impact

Merging the installer changes to the default branch breaks the documented installation command immediately, before a new archive-based release exists. Explicit installation or downgrade to every older tag also stops working.

Acceptance criteria

• The installers select raw-binary vs archive layout based on the resolved release version, or otherwise retain a working legacy path for every supported published tag.
• Bare latest succeeds while latest is still a raw-binary release.
• --version v0.4.1 and --version v0.5.0-rc4 are covered by tests.
• Archive extraction is tested against the first tag that actually publishes archives.
• Release documentation names the real transition tag rather than retroactively claiming rc4 shipped archives.

Related: #349, PR #352.

[alpCaner]

Fixed on dev in ac79d4c (PR #352). dev IS this repo's default branch, so Closes does fire here -- but this issue was filed AFTER the PR body's closing-keyword list was written, so it was never in it. Closed by hand; a merged PR body cannot close retroactively.

Both installers select raw-vs-archive from the release's own checksums.txt -- archive name first, raw as fallback -- so every published tag installs. Not from a version comparison, which is a second source of truth that drifts. --version v0.4.1, v0.5.0-rc4 and the first archive tag are covered; the POSIX half was re-run under WSL Ubuntu-24.04 where it executes rather than skips (8 passed, 7 skipped; the 7 are the pwsh cases, which pass on Windows).

The real transition tag is v0.5.0, stated accurately in the docs -- rc4 ships raw.