Performance Monitoring Enhancement: runtime metrics, memory profiling, regression detection, and dashboard

[Copilot]

• Create RuntimeMetricsCollector in ACATCore/Utility/Metrics/ (Runtime Metrics Collection #198)
• Create MemoryProfiler in ACATCore/Utility/Diagnostics/ (Memory Profiling Integration #199)
• Create PerformanceBaseline and PerformanceRegressionDetector in ACATCore/Utility/Diagnostics/ (Performance Regression Detection #200)
• Create PerformanceDashboard WPF window in ACAT.Extensions.UI/Diagnostics/ (Performance Dashboard #201)
• Update PerformanceMonitor.cs to integrate new components
• Add ACATCore.Tests.Performance test project with tests for new components
• Update CI workflow (build.yml, test.yml) to run new performance tests
• Update ACAT.Core.csproj and ACAT.Extensions.UI.csproj to include new files
• Add ACATCore.Tests.Performance to ACAT.sln
• Fix spelling in doc comments (code review feedback)
• Fix build error: JsonSerializer.Serialize/Deserialize shadowed by ACAT.Core.Utility.JsonSerializer
• Add usage documentation to PerformanceDashboard.xaml (XAML comment block) and PerformanceDashboard.xaml.cs (XML doc with code examples)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Performance Monitoring Enhancement</issue_title>
<issue_description>Expand performance monitoring capabilities beyond startup metrics.

Key Deliverables:

• Runtime performance metrics
• Memory profiling integration
• Performance regression detection
• Dashboard and reporting

Benefits:

• Proactive performance issues
• Track improvements
• Prevent regressions
• Better diagnostics

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🔗 Dependencies

• Depends on: Phase 1 Complete ΓÅ│ (not yet created)

Epic: Phase 2 - Core Infrastructure Modernization

Estimated Effort: 1-2 weeks

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📋 Tasks

• Runtime Metrics Collection #198 Runtime Metrics Collection
• Memory Profiling Integration #199 Memory Profiling Integration
• Performance Regression Detection #200 Performance Regression Detection
• Performance Dashboard #201 Performance Dashboard

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Performance Monitoring Enhancement #193

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[michaelbeale-IL]

@copilot I think there are build errors. can you check it out?

[Copilot]

@copilot I think there are build errors. can you check it out?

Fixed in commit 4bb4b61.

The build errors were in PerformanceBaseline.cs:

error CS1501: No overload for method 'Serialize' takes 2 arguments
error CS1501: No overload for method 'Deserialize' takes 2 arguments

The root cause: PerformanceBaseline.cs lives in the ACAT.Core.Utility.Diagnostics namespace, which is a child of ACAT.Core.Utility. C# resolves unqualified names in parent namespaces before using directives, so JsonSerializer resolved to the custom ACAT.Core.Utility.JsonSerializer class (which only takes 1 argument) instead of System.Text.Json.JsonSerializer.

The fix follows the same pattern used in the existing JsonConfigurationLoader.cs — use the fully qualified System.Text.Json.JsonSerializer.Serialize(...) and System.Text.Json.JsonSerializer.Deserialize<T>(...) to avoid the ambiguity.

[michaelbeale-IL]

@copilot can you document how this should be used?

[Copilot]

Done in commit 49c954f. Added documentation in two places:

1. PerformanceDashboard.xaml — a prominent comment block at the top of the file with a full usage guide covering quick start, shared collectors, custom baselines, export options, and a description of each panel.

2. PerformanceDashboard.xaml.cs — expanded XML doc <remarks> on the class with <code> examples for all three usage patterns:

// Minimal — self-contained
var dashboard = new PerformanceDashboard();
dashboard.Show();

// Shared collectors (show data already gathered by the app)
var dashboard = new PerformanceDashboard(collector, profiler);
dashboard.Show();

// Custom regression thresholds
PerformanceBaselineData baseline = PerformanceBaseline.Load(baselinePath);
var dashboard = new PerformanceDashboard(collector, profiler, baseline);
dashboard.Show();