feat: implement dynamic attribute merging for test data collectors an…

[thomhurst]

Fixes #4186

[github-actions]

Summary

This PR fixes dynamic tests to inherit attributes from their test class and assembly.

Critical Issues

None found ✅

Suggestions

Performance: Attribute Collection Allocation

The new GetDynamicTestAttributes method creates a new List for every dynamic test during discovery (hot path). Consider:

• Early-exit when TestClassType is null
• Pre-allocate list capacity based on result.Attributes.Count + estimated class/assembly attributes
  However, this may be premature optimization - measure first if concerned.

Test Validation Timing

In DynamicTestInheritedAttributesTests line 78, the Task.Delay(100) seems fragile for detecting overlaps if tests run slowly. Consider more deterministic synchronization or longer buffer.

Verdict

✅ APPROVE - Implementation correctly fixes issue #4186 with proper dual-mode support and good test coverage.