fix(admin): decode beta.9 response envelopes

[cxymds]

Related issue

• Resolves CLI: No cluster/system/disk informationen rustfs#4927

Background

RustFS 1.0.0-beta.9 wraps /rustfs/admin/v3/info in an info field and targeted /rustfs/admin/v3/pools/status responses in a pool field. The CLI previously deserialized those envelopes directly into default-valued domain models, so the commands succeeded while displaying empty cluster or pool data.

Root cause

ClusterInfo and PoolStatus use Serde defaults and accept unknown fields. The new beta.9 envelope fields were ignored, producing default domain objects instead of a deserialization error.

Solution

• decode the beta.9 info envelope before returning ClusterInfo
• decode the beta.9 pool envelope before returning targeted PoolStatus
• reject legacy flat beta.8 payloads instead of silently returning defaults
• cover cluster, server, disk, and targeted pool status output
• verify pool list, decommission, rebalance, expand, heal, and site replication remain unaffected

User impact

rc admin info cluster, rc admin info server, rc admin info disk, and targeted rc admin pool status now display the data returned by RustFS beta.9.

Validation

• cargo fmt --all --check
• cargo clippy --workspace -- -D warnings
• cargo test --workspace