feat(release): application release command family

[JulianRuiseco]

Objective

fslabscli is the de facto location for CI logic. This PR gives it the
application release pipeline: the logic behind fsl_libs' release workflows
(fslabs/fsl_libs#4230 rewrites them as thin, pinned invocations of these
commands), which previously lived as bash under that repo's
.github/scripts/.

It also makes fslabscli the single owner of the library-vs-application
release boundary: release classify shares the publish- tag-prefix
constant with the publish path, so a library release created by
fslabscli publish is skipped by the app pipeline by construction.

Solution

This PR is the pipeline CORE - everything a release cannot ship without.
The operational periphery (resolve, record, healthcheck,
cleanup-drafts) stacks on top in a follow-up PR so each unit stays
reviewable.

A release subcommand family (cargo fslabscli release <cmd>):

Command	Purpose
classify	Library skip vs validated <app>-<version> app release; app discovery from [package.metadata.fslabs.release] across every git-tracked manifest, including excluded workspaces
verify-production	Tag-resolved revision (never target_commitish), ancestry of main, workspace version binding, green check runs
probe-store	Conditional-write go/no-go gate against a deployed store
publish	Atomic publication: signature re-verification, monotonicity from committed manifests, read-back before the manifest commit point, index CAS
promote	The only writer of channels.json; backward gate re-runs inside the CAS retry loop; rollback = acknowledged backward move with provenance
bundle-linux	cargo-deb + bundle-nothing AppImage with a glibc-floor assertion
sign-linux	Detached OpenPGP signatures in a throwaway GNUPGHOME

The manifest / index / channels.json serde definitions in
release/types.rs are the single source of truth for the published object
shapes; storage semantics live in release/store.rs on the existing
opendal dependency (put-if-absent via if_not_exists, ETag If-Match CAS
with the transform re-run on every retry). New deps: semver,
thiserror. All commands run on Linux runners, so the existing
linux-musl release asset remains the only distributed binary.

This family supersedes the legacy publish.binary installer/channel model
in check_workspace/binary.rs (nightly/alpha blob channels); deprecating
and removing that is follow-up work after the fsl_libs cutover.

Size

One squashed commit, ~3.4k lines: seven subcommands, their 45 unit tests
(the ported specification of the bash this replaces), and the shared
contract types / storage / HTTP / keyring modules. The doc comments carry
the published contract (why the manifest is written last, why
monotonicity ignores index.json, why a backward move re-validates inside
the CAS loop) and are load-bearing. Review path: types.rs + store.rs
first (the contract), then classify/publish/promote (the decisions), then
bundle/sign/probe (tool wrappers). The stacked periphery PR is ~1.3k.

Testing

• cargo test: 324 passed (58 in the release module: classification
  grammar and tag-boundary scenarios, conditional-write semantics, the
  backward-move gate and provenance cap, manifest completeness both
  directions, glibc symbol parsing, api-url normalisation).
• End to end with the built binary against a throwaway MinIO:
  sign-linux -> publish 1.0.0 and 1.1.0 (six objects each, manifest last;
  re-publishing 1.0.0 refused with the version-spent error) -> promote
  latest -> unacknowledged backward move refused, acknowledged one records
  backward: true + reason -> resolve --download digest- and
  GPG-verifies against the published key -> healthcheck reports the
  surface healthy, and names both digests when an object is tampered.
• Against the real fsl_libs tree: release classify discovers
  spatial_engine from its metadata in the excluded fdk_apps workspace,
  routes production/preview correctly, and skips publish-* releases
  including null-name ones.
• Three integration defects were found by those live runs and fixed (all
  invisible to unit tests): toml 0.9 document-vs-value parsing, clap's
  propagated auto --version flag colliding with --version arguments,
  and opendal expressing S3 If-None-Match:* as if_not_exists.

Known wart: main.rs requires a git root before dispatch, so
release resolve panics outside a checkout; relaxing that touches shared
code and is left for a follow-up.

Release

After merge, tag a release so fslabs/fsl_libs#4230 can set its pin
(version + binary sha256) in .github/actions/install-fslabscli.

[fslabs-bot]

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