- `bitfun update --check` printed "is up to date" right after announcing an
  available version; add a distinct `Available` outcome.
- Bound the startup auto-update check with a 90s budget so a stalled mirror
  cannot wedge interactive TUI launch behind a 120s-per-request client.
- Resolve the auto-check stamp through `CliConfig::config_dir()` instead of a
  hardcoded `~/.config/bitfun`.
- Strip SemVer build metadata from Linux asset names: GitHub rewrites `+` in
  uploaded release asset filenames, which made every nightly URL in
  linux-binaries.json a 404. Guard it in the manifest generator too.
- openbitfun-release-sync.sh no longer deletes the published
  linux-binaries.json on a transient fetch failure; retry, and only remove it
  on a definitive 404.
- Relay release deploy: trap INT/TERM so a cancelled wizard restores the
  renamed backup container instead of leaving the relay down, sweep orphaned
  backups, and honor RELAY_HOST_BIND_IP like docker-compose.yml does.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cli-package.yml and desktop-package.yml both run on `release: published`, and
both built the Linux CLI with the same version derivation, so both uploaded
byte-identical asset names to the same release. softprops/action-gh-release
deletes a same-named asset before writing, so the two runs could destroy each
other's upload — on top of two redundant full Rust builds per release.

Ownership is forced by two constraints: cli-package.yml never runs for nightly
(a GITHUB_TOKEN-created release does not trigger workflows), and
linux-binaries.json must be written by a job that physically holds all four
archives. Both point at linux-binaries.yml, so drop the Linux targets from
cli-package.yml's matrix.

SHA256SUMS now covers the macOS and Windows archives only; the per-archive
.sha256 sidecar remains the complete surface on every platform and channel.
Documented in the CLI README and locked with contract tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>