fix(tests): Fix test process hanging by removing background tasks

Root cause: Fire-and-forget Task.Run in ResourceManager.MaxConcurrency
setter was preventing test process from exiting.

Changes:
1. Removed Task.Run + Task.Delay pattern in ResourceManager
   - Dispose old semaphore immediately instead of after delay
   - Operations holding semaphore will complete normally

2. Added xunit.runner.json to disable parallel test execution
   - Prevents resource contention in CI environments
   - maxParallelThreads: 1 for deterministic execution

Expected: Tests complete in ~2 seconds instead of timing out

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Ahmed Mustafa

.claude/settings.local.json

@@ -13,7 +13,9 @@
       "Bash(gh:*)",
       "Bash(git push:*)",
       "Bash(find:*)",
-      "Bash(timeout 10 dotnet test:*)"
+      "Bash(timeout 10 dotnet test:*)",
+      "WebFetch(domain:github.com)",
+      "Bash(timeout 120 dotnet test:*)"
     ]
   }
 }

src/DotNetDevMCP.Orchestration/ResourceManager.cs

@@ -48,12 +48,9 @@ public int MaxConcurrency
                     _semaphore = new SemaphoreSlim(value, value);
                     _maxConcurrency = value;
 
-                    // Dispose old semaphore after a delay to allow current operations to complete
-                    Task.Run(async () =>
-                    {
-                        await Task.Delay(1000);
-                        oldSemaphore.Dispose();
-                    });
+                    // Dispose old semaphore immediately - operations already holding the semaphore
+                    // will complete normally, and new operations will use the new semaphore
+                    oldSemaphore.Dispose();
                 }
             }
         }

tests/DotNetDevMCP.Core.Tests/DotNetDevMCP.Core.Tests.csproj

@@ -19,6 +19,12 @@
     <Using Include="Xunit" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Content Include="xunit.runner.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
   <ItemGroup>
     <ProjectReference Include="..\..\src\DotNetDevMCP.Orchestration\DotNetDevMCP.Orchestration.csproj" />
   </ItemGroup>

tests/DotNetDevMCP.Core.Tests/xunit.runner.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://xunit.net/schema/current/xunit.runner.schema.json",
+  "parallelizeAssembly": false,
+  "parallelizeTestCollections": false,
+  "maxParallelThreads": 1
+}