feat: extend hotpath coverage across crates (#5505)

Add opt-in hotpath feature surfaces to every workspace crate and wire the root rustfs feature passthrough for function, allocation, and CPU profiling.

Add a focused set of function-level measurements for scanner, heal, lock, target replay, IAM, KMS, Keystone, trusted proxy, and capacity paths without adding request-scoped primitive wrappers.

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

crates/heal/src/heal/erasure_healer.rs

@@ -159,6 +159,7 @@ impl ErasureSetHealer {
 
     /// execute erasure set heal with resume
     #[tracing::instrument(skip(self, buckets), fields(set_disk_id = %set_disk_id, bucket_count = buckets.len()))]
+    #[hotpath::measure]
     pub async fn heal_erasure_set(&self, buckets: &[String], set_disk_id: &str) -> Result<()> {
         debug!(
             target: "rustfs::heal::erasure_healer",

crates/heal/src/heal/task.rs

@@ -584,6 +584,7 @@ impl HealTask {
     }
 
     #[tracing::instrument(skip(self), fields(task_id = %self.id, heal_type = ?self.heal_type))]
+    #[hotpath::measure]
     pub async fn execute(&self) -> Result<()> {
         // update status and timestamps atomically to avoid race conditions
         let now = SystemTime::now();
@@ -759,6 +760,7 @@ impl HealTask {
 
     // specific heal implementation method
     #[tracing::instrument(skip(self), fields(bucket = %bucket, object = %object, version_id = ?version_id))]
+    #[hotpath::measure]
     async fn heal_object(&self, bucket: &str, object: &str, version_id: Option<&str>) -> Result<()> {
         debug!(
             target: "rustfs::heal::task",
@@ -1404,6 +1406,7 @@ impl HealTask {
         self.heal_bucket_objects(bucket, prefix).await
     }
 
+    #[hotpath::measure]
     async fn heal_bucket_objects(&self, bucket: &str, prefix: &str) -> Result<()> {
         let mut continuation_token: Option<String> = None;
         let mut scanned = 0u64;