Bump version to 4.0.2 and update README formatting

- Incremented project version to 4.0.2 in the .csproj file.
- Reformatted thread-safety section in README for clarity.
- Updated version history date for 4.0.0 to December 2025.

Author: snoekiede

EsoxSolutions.ObjectPool/EsoxSolutions.ObjectPool.csproj

@@ -10,8 +10,8 @@
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <RepositoryUrl>https://github.com/snoekiede/EsoxSolutions.ObjectPool</RepositoryUrl>
     <PackageTags>objectpool;threadsafe;async;performance;metrics;healthchecks;dependencyinjection;opentelemetry;warmup;eviction;ttl;circuitbreaker;lifecycle;multitenancy;scopedpools</PackageTags>
-    <AssemblyVersion>4.0.1</AssemblyVersion>
-    <FileVersion>4.0.1</FileVersion>
+    <AssemblyVersion>4.0.2</AssemblyVersion>
+    <FileVersion>4.0.2</FileVersion>
     <GenerateDocumentationFile>True</GenerateDocumentationFile>
     <Title>Production-Ready Object Pool for .NET with Complete Observability</Title>
     <Authors>Iede Snoek</Authors>

README.md

@@ -375,14 +375,14 @@ foreach (var kv in metrics)
 ## Thread-Safety
 
 All pool operations are thread-safe using lock-free `ConcurrentStack<T>` and `ConcurrentDictionary<T, byte>`:
-- ? Tested with 500 concurrent threads
-- ? Race condition free
-- ? No blocking locks in hot paths
-- ? Atomic operations for critical sections
+- Tested with 500 concurrent threads
+- Race condition free
+- No blocking locks in hot paths
+- Atomic operations for critical sections
 
 ## Version History
 
-### 4.0.0 (Current) - January 2025
+### 4.0.0 (Current) - December 2025
 - **Complete Production-Ready Suite**: All enterprise features integrated and tested
 - **Dependency Injection**: First-class ASP.NET Core and Generic Host support
 - **Health Checks**: ASP.NET Core Health Checks integration with custom thresholds