fix(obs): isolate process sampler windows (#4492)

* fix(obs): isolate process sampler windows

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- add a reusable ProcessSampler so callers can own independent sysinfo refresh windows
- wire separate sampler instances for obs metrics scheduling and memory observability
- keep compatibility helpers while avoiding cross-task CPU and disk delta interference

Co-Authored-By: heihutu <heihutu@gmail.com>

* fix(obs): import process sampler bundle helper

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- import collect_process_metric_bundle_with in the metrics scheduler
- drop the stale collect_process_metric_bundle import after switching scheduler sampling to independent process samplers

Co-Authored-By: heihutu <heihutu@gmail.com>

* fix(obs): move process sampler into blocking task

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- move the memory observability process sampler into the spawn_blocking closure
- satisfy the closure static lifetime required by tokio while keeping the isolated sampler design intact

Co-Authored-By: heihutu <heihutu@gmail.com>

---------

Co-authored-by: heihutu <heihutu@gmail.com>

crates/lock/src/fast_lock/manager.rs

@@ -372,12 +372,17 @@ impl FastObjectLockManager {
 
     /// Start background cleanup task
     fn start_cleanup_task(&self) {
+        let Ok(handle) = tokio::runtime::Handle::try_current() else {
+            tracing::debug!("Skipping fast lock cleanup task startup because no Tokio runtime is active");
+            return;
+        };
+
         let shards = self.shards.clone();
         let metrics = self.metrics.clone();
         let cleanup_interval = self.config.cleanup_interval;
         let _max_idle_time = self.config.max_idle_time;
 
-        let handle = tokio::spawn(async move {
+        let handle = handle.spawn(async move {
             let mut interval = interval(cleanup_interval);
 
             loop {
@@ -531,6 +536,12 @@ mod tests {
         manager.shutdown().await;
     }
 
+    #[test]
+    fn test_manager_construction_without_runtime_does_not_panic() {
+        let manager = FastObjectLockManager::new();
+        assert_eq!(manager.shards.len(), crate::fast_lock::DEFAULT_SHARD_COUNT);
+    }
+
     #[tokio::test]
     async fn test_list_locks_reports_held_locks() {
         let manager = FastObjectLockManager::new();