Fix MSTest 4.0 analyzer errors

- MSTEST0001: Enable test parallelization at method level
- MSTEST0044: Replace obsolete DataTestMethod with TestMethod (2 occurrences)

MSTest 4.0 requires explicit parallelization configuration and no longer
uses DataTestMethod - TestMethod with DataRow attributes is the new pattern.

Author: claude

test/NosCore.Networking.Tests/LogLanguageTests.cs

@@ -27,7 +27,7 @@ public LogLanguageTests()
         }
 
         [TestCategory("OPTIONAL-TEST")]
-        [DataTestMethod]
+        [TestMethod]
         [DataRow(RegionType.EN)]
         [DataRow(RegionType.CS)]
         [DataRow(RegionType.DE)]
@@ -51,7 +51,7 @@ public void CheckEveryLanguageValueSet(RegionType type)
             }
         }
 
-        [DataTestMethod]
+        [TestMethod]
         [DataRow(RegionType.EN)]
         [DataRow(RegionType.CS)]
         [DataRow(RegionType.DE)]

test/NosCore.Networking.Tests/NosCore.Networking.Tests.csproj

@@ -6,6 +6,13 @@
 		<IsPackable>false</IsPackable>
 		<TreatWarningsAsErrors>true</TreatWarningsAsErrors>
 	</PropertyGroup>
+
+	<ItemGroup>
+		<AssemblyAttribute Include="Microsoft.VisualStudio.TestTools.UnitTesting.ParallelizeAttribute">
+			<_Parameter1>Microsoft.VisualStudio.TestTools.UnitTesting.ExecutionScope.MethodLevel</_Parameter1>
+			<_Parameter1_TypeName>Microsoft.VisualStudio.TestTools.UnitTesting.ExecutionScope</_Parameter1_TypeName>
+		</AssemblyAttribute>
+	</ItemGroup>
 
 	<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
 		<OutputPath>..\..\build\</OutputPath>