* feat(ecstore): add object lock diagnostics
Add configurable namespace lock diagnostics for object operations so production contention can be traced by operation, owner, and key.
Wrap object read/write lock acquisition in diagnostic guards across get, head, put, delete, copy, and multipart flows, and log slow acquisition and long hold durations behind new RUSTFS_OBJECT_LOCK_DIAG_* settings.
Verification:
- make pre-commit
* feat(obs): expose object lock diagnostics metrics
Add Prometheus metrics and Grafana panels for object namespace lock diagnostics, covering slow acquire counts, slow hold counts, acquire duration, hold duration, and the diagnostics-enabled state.
Adopt PR review feedback by keeping diagnostic guards alive through the guarded operation so long-hold warnings and metrics are emitted, reusing shared env helpers, and reducing default-path overhead when diagnostics are disabled.
Verification:
- cargo check -p rustfs-ecstore -p rustfs-io-metrics
- cargo test -p rustfs-ecstore store::object -- --nocapture
- make pre-commit
* perf(obs): reduce object lock diag overhead
Avoid repeated environment parsing on hot object-lock paths by caching the diagnostics-enabled flag, and stop allocating label strings for object lock metrics by recording static labels directly.
Strengthen io-metrics tests by using a local recorder and asserting that the expected object lock diagnostic counters, gauges, and histograms are emitted.
Verification:
- cargo check -p rustfs-ecstore -p rustfs-io-metrics
- cargo test -p rustfs-io-metrics -- --nocapture
- make pre-commit
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