feat(tasks): add thread names for spawned blocking tasks

Closes #20430 by adding descriptive thread names to blocking task pools,
making them identifiable in profilers like Samply.

Thread naming convention (kept under 15-char Linux limit):
- reth-node-{idx}: Main node runtime threads
- reth-eng-{idx}: Engine WorkloadExecutor threads
- reth-blk-{idx}: BlockingTaskPool rayon threads

crates/cli/runner/src/lib.rs

@@ -214,7 +214,16 @@ pub struct CliContext {
 /// Creates a new default tokio multi-thread [Runtime](tokio::runtime::Runtime) with all features
 /// enabled
 pub fn tokio_runtime() -> Result<tokio::runtime::Runtime, std::io::Error> {
-    tokio::runtime::Builder::new_multi_thread().enable_all().build()
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    static THREAD_IDX: AtomicUsize = AtomicUsize::new(0);
+
+    tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .thread_name_fn(|| {
+            let idx = THREAD_IDX.fetch_add(1, Ordering::Relaxed);
+            format!("reth-node-{idx}")
+        })
+        .build()
 }
 
 /// Runs the given future to completion or until a critical task panicked.

crates/engine/tree/src/tree/payload_processor/executor.rs

@@ -1,6 +1,12 @@
 //! Executor for mixed I/O and CPU workloads.
 
-use std::{sync::OnceLock, time::Duration};
+use std::{
+    sync::{
+        atomic::{AtomicUsize, Ordering},
+        OnceLock,
+    },
+    time::Duration,
+};
 use tokio::{
     runtime::{Builder, Handle, Runtime},
     task::JoinHandle,
@@ -51,6 +57,8 @@ impl WorkloadExecutorInner {
                 static RT: OnceLock<Runtime> = OnceLock::new();
 
                 let rt = RT.get_or_init(|| {
+                    static THREAD_IDX: AtomicUsize = AtomicUsize::new(0);
+
                     Builder::new_multi_thread()
                         .enable_all()
                         // Keep the threads alive for at least the block time, which is 12 seconds
@@ -60,6 +68,10 @@ impl WorkloadExecutorInner {
                         // new block, and instead reuse the existing
                         // threads.
                         .thread_keep_alive(Duration::from_secs(15))
+                        .thread_name_fn(|| {
+                            let idx = THREAD_IDX.fetch_add(1, Ordering::Relaxed);
+                            format!("reth-eng-{idx}")
+                        })
                         .build()
                         .unwrap()
                 });

crates/tasks/src/pool.rs

@@ -73,7 +73,7 @@ impl BlockingTaskPool {
     /// If a different stack size or other parameters are needed, they can be configured via
     /// [`rayon::ThreadPoolBuilder`] returned by [`Self::builder`].
     pub fn build() -> Result<Self, rayon::ThreadPoolBuildError> {
-        Self::builder().build().map(Self::new)
+        Self::builder().thread_name(|i| format!("reth-blk-{i}")).build().map(Self::new)
     }
 
     /// Asynchronous wrapper around Rayon's