feat: add pool decommission lifecycle

[GatewayJ]

Type of Change

• New Feature
• Bug Fix
• Documentation
• Performance Improvement
• Test/CI
• Refactor
• Other:

Related Issues

N/A

Summary of Changes

• Add pool lifecycle/decommission request CRD fields, status fields, RustFS admin client support, and console API endpoints.
• Align post-decommission pool removal with MinIO Operator behavior: after decommission completion, removing the pool from spec.pools allows the operator to remove the matching StatefulSet and emit PoolRemoved.
• Reject stray cancel requests without an active decommission request/status, remove stale lifecycle requests when pools are removed or re-added, and keep tenants reconciling during decommission cleanup.
• Expose pool lifecycle and decommission progress through the console API and OpenAPI/types.

Checklist

• I have read and followed the CONTRIBUTING.md guidelines
• Passed make pre-commit (fmt-check + clippy + test + console-lint + console-fmt-check)
• Added/updated necessary tests
• Documentation updated (if needed)
• CHANGELOG.md updated under [Unreleased] (N/A: repository does not currently contain CHANGELOG.md)
• CI/CD passed (if applicable)

Impact

• Breaking change (CRD/API compatibility)
• Requires doc/config/deployment update
• Other impact: Adds pool lifecycle/decommission fields to the Tenant CRD and console API.

Verification

make pre-commit

Additional Notes

The cleanup flow intentionally mirrors MinIO Operator's documented flow: run decommission, wait until complete, then remove the decommissioned pool from the Tenant spec so the operator can delete the stale StatefulSet while retaining PVCs.

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Keep completedAt stable after terminal decommission

completed_at() returns now_rfc3339() every time a pool is polled in a terminal phase (Complete/Canceled/Failed), so the generated status is always different even when nothing changed. Because the controller watches Tenant updates, this can cause a self-triggering reconcile loop (status patch → watch event → reconcile → new timestamp → patch) for canceled/failed requests that do not set a requeue. Persist the first completion time (or reuse the existing status value) instead of regenerating it on every pass.

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