feat(metrics): add timing instrumentation for cross-client execution metrics

Pipe timing data to EvmMetrics for state_read_ms, state_hash_ms, and commit_ms:

- WorldStateMetricsDecorator: pipe existing timing to EvmMetrics for
  RecalculateStateRoot, Commit (both overloads), and CommitTree
- StateProvider.GetState: add timing around DB reads (not cache hits)
- PersistentStorageProvider.LoadFromTree: add timing for storage reads

Uses Stopwatch.GetTimestamp()/GetElapsedTime() with TimeSpan.Ticks
(100ns precision) for minimal overhead (~10-20ns per measurement).

Author: CPerezz

src/Nethermind/Nethermind.State/PersistentStorageProvider.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -352,9 +353,12 @@ public void WarmUp(in StorageCell storageCell, bool isEmpty)
 
     private ReadOnlySpan<byte> LoadFromTree(in StorageCell storageCell)
     {
+        long start = Stopwatch.GetTimestamp();
         // Track storage read for execution metrics
         EvmMetrics.IncrementStorageReads();
-        return GetOrCreateStorage(storageCell.Address).LoadFromTree(storageCell);
+        ReadOnlySpan<byte> result = GetOrCreateStorage(storageCell.Address).LoadFromTree(storageCell);
+        EvmMetrics.AddStateReadTime(Stopwatch.GetElapsedTime(start).Ticks);
+        return result;
     }
 
     private void PushToRegistryOnly(in StorageCell cell, byte[] value)

src/Nethermind/Nethermind.State/StateProvider.cs

@@ -718,10 +718,12 @@ public bool WarmUp(Address address)
             ref ChangeTrace accountChanges = ref CollectionsMarshal.GetValueRefOrAddDefault(_blockChanges, addressAsKey, out bool exists);
             if (!exists)
             {
+                long start = Stopwatch.GetTimestamp();
                 Metrics.IncrementStateTreeReads();
                 // Track account read for execution metrics (DB reads only, not cache hits)
                 EvmMetrics.IncrementAccountReads();
                 Account? account = _tree.Get(address);
+                EvmMetrics.AddStateReadTime(Stopwatch.GetElapsedTime(start).Ticks);
 
                 accountChanges = new(account, account);
             }

src/Nethermind/Nethermind.State/WorldStateMetricsDecorator.cs

@@ -11,6 +11,7 @@
 using Nethermind.Evm.State;
 using Nethermind.Evm.Tracing.State;
 using Nethermind.Int256;
+using EvmMetrics = Nethermind.Evm.Metrics;
 
 namespace Nethermind.State;
 
@@ -48,7 +49,10 @@ public void RecalculateStateRoot()
     {
         long start = Stopwatch.GetTimestamp();
         innerState.RecalculateStateRoot();
-        StateMerkleizationTime += Stopwatch.GetElapsedTime(start).TotalMilliseconds;
+        TimeSpan elapsed = Stopwatch.GetElapsedTime(start);
+        StateMerkleizationTime += elapsed.TotalMilliseconds;
+        // Pipe to cross-client execution metrics
+        EvmMetrics.AddStateHashTime(elapsed.Ticks);
     }
 
     public Hash256 StateRoot => innerState.StateRoot;
@@ -88,23 +92,41 @@ public void Commit(IReleaseSpec releaseSpec, bool isGenesis = false, bool commit
     {
         long start = Stopwatch.GetTimestamp();
         innerState.Commit(releaseSpec, isGenesis, commitRoots);
+        TimeSpan elapsed = Stopwatch.GetElapsedTime(start);
         if (commitRoots)
-            StateMerkleizationTime += Stopwatch.GetElapsedTime(start).TotalMilliseconds;
+        {
+            StateMerkleizationTime += elapsed.TotalMilliseconds;
+            EvmMetrics.AddStateHashTime(elapsed.Ticks);
+        }
+        else
+        {
+            EvmMetrics.AddCommitTime(elapsed.Ticks);
+        }
     }
 
     public void Commit(IReleaseSpec releaseSpec, IWorldStateTracer tracer, bool isGenesis = false, bool commitRoots = true)
     {
         long start = Stopwatch.GetTimestamp();
         innerState.Commit(releaseSpec, tracer, isGenesis, commitRoots);
+        TimeSpan elapsed = Stopwatch.GetElapsedTime(start);
         if (commitRoots)
-            StateMerkleizationTime += Stopwatch.GetElapsedTime(start).TotalMilliseconds;
+        {
+            StateMerkleizationTime += elapsed.TotalMilliseconds;
+            EvmMetrics.AddStateHashTime(elapsed.Ticks);
+        }
+        else
+        {
+            EvmMetrics.AddCommitTime(elapsed.Ticks);
+        }
     }
 
     public void CommitTree(long blockNumber)
     {
         long start = Stopwatch.GetTimestamp();
         innerState.CommitTree(blockNumber);
-        StateMerkleizationTime += Stopwatch.GetElapsedTime(start).TotalMilliseconds;
+        TimeSpan elapsed = Stopwatch.GetElapsedTime(start);
+        StateMerkleizationTime += elapsed.TotalMilliseconds;
+        EvmMetrics.AddStateHashTime(elapsed.Ticks);
     }
 
     public ArrayPoolList<AddressAsKey>? GetAccountChanges() => innerState.GetAccountChanges();