feat: gate new Cargo publication metadata

[JulianRuiseco]

Objective

Require explicit approval before a crate becomes metadata-marked for Cargo publication, and detect approved crates that are still absent from the target registry.

Solution

Add check-cargo-publish-policy with separate approval and registry modes. It reads committed Cargo manifests from Git objects, fails closed on invalid metadata or registry responses, and treats a crate name as present regardless of version or yank state.

The command never publishes. Tagged releases continue to check exact dependency versions, publish missing dependencies before dependants, and skip a dependant if its dependency fails.

Testing

• RUSTC_WRAPPER= cargo test: 307 passed
• RUSTC_WRAPPER= cargo clippy --all-targets -- -D warnings
• RUSTC_WRAPPER= cargo check
• cargo +nightly fmt --all -- --check
• Compared the current fsl_libs base and head with --check approval: no newly marked packages

Rollout

Release this as v2.48.2 before enabling the dependent fsl_libs workflow or Prow registry policy job.

[fslabs-bot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[fslabs-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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Details

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• OWNERS

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