feat(rc-site-replication)!: expose persisted resync snapshots

[cxymds]

Closes rustfs/backlog#1419

Parent: rustfs/backlog#1411
Roadmap: rustfs/backlog#1381, rustfs/backlog#1361
Depends on: #290 and rustfs/backlog#1418

Background

RustFS beta10 exposes PUT /rustfs/admin/v3/site-replication/resync/op, but its status response is a persisted snapshot of the last start or cancel handler invocation rather than live worker state. Without a typed and bounded CLI workflow, users can overstate lifecycle progress or blindly retry a mutation whose side effects may already have happened.

Solution

• add rc admin replicate resync start|status|cancel with exact peer selection and pre-network --yes confirmation for mutations
• send the complete typed peer document using the exact beta10 query and body contract
• expose operation IDs, ordered per-bucket results, top-level details, and safe future metadata through output-v3 admin_operations
• label status as persisted_last_operation and lifecycle as unknown
• preserve partial/all-bucket failures in output and return General exit 1
• bound requests and responses, disable redirect replay, and distinguish local request rejection from an attempted mutation
• report disconnects, malformed/oversized mutation responses, and unclassified server failures as unknown outcomes with no blind retry guidance
• redact credentials recursively without changing the unredacted protocol success/failure classification
• document current RustFS overlap, cancellation, persistence, atomicity, and live-status limitations

BREAKING contract note

This PR updates the protected docs/reference/rc/ behavior contract and is intentionally marked BREAKING. The new commands are additive and use the existing output-v3 admin_operations schema, so no schema-version migration is required. Automation must treat result.lifecycle_state as unknown and must not interpret resync status snapshots as live progress.

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace -- --test-threads=1 — 1230 passed, 0 failed, 1 ignored
• independent final review — no actionable findings

[cxymds]

Implementation and validation are complete for the current stacked revision (34a357c).

Validation:

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace -- --test-threads=1 — 1230 passed, 0 failed, 1 ignored
• all required GitHub checks passed on Linux, macOS, and Windows
• RustFS latest smoke, CLI contract, Golden, documentation, MSRV, protected-files, and dependency advisory checks passed
• independent final review found no actionable issues

The PR remains Draft and correctly targets cxymds/issue-1418-site-replication-edit.