[cxymds]

Summary

Add rc support for the additive pool diagnostic fields emitted by the RustFS partial-outage-safe pool status API.

Changes

• Preserve the existing lifecycle status field and decode availability, poolMetadataStatus, rebalanceMetadataStatus, capacityStatus, and observedAt.
• Default omitted diagnostic fields to unknown when talking to older RustFS servers.
• Show availability, metadata freshness, and capacity observation quality in human-readable pool output.
• Extend the output v2 schema with the optional diagnostic properties.
• Add compatibility coverage for old server responses and current diagnostic responses.

Verification

• cargo fmt --all --check passed.
• cargo clippy --workspace --all-targets --locked -- -D warnings passed.
• cargo test --workspace --locked passed.
• cargo test --package rustfs-cli --test golden --features golden --locked passed.
• cargo deny check advisories passed.
• JSON schema parsing and git diff --check passed.

The branch includes the merged dependency maintenance from #395, which resolves the earlier Clippy and dependency advisory failures.

Compatibility

This PR is additive and is intended to land with rustfs/rustfs#8995. Older RustFS servers remain usable; their omitted diagnostic fields are represented as unknown rather than inferred as healthy.