[Unity] compilation-error state remains latched after a successful subsequent compile

[zelerj]

Environment

• Unity 6000.4.0f1
• Coplay 8.20.3 at commit 620446a

Reproduction

1. Introduce a transient C# compilation error.
2. Let Coplay observe the failed compilation.
3. Fix the script and wait for Unity to finish a clean compilation cycle.
4. Invoke execute_script.

Actual behavior

execute_script remains rejected as if the project were still invalid even though the Unity Console, Bee assemblies, and Library/ScriptAssemblies are clean.

Expected behavior

The gate should reflect the most recently completed compilation cycle, rather than retaining a historical OR of earlier failures.

Suggested fix

Reset the per-cycle error accumulator on CompilationPipeline.compilationStarted, aggregate only errors from the current cycle, then publish the result atomically from assemblyCompilationFinished / compilationFinished.

This was reproduced while automating ForgeUI validation in a live Unity 6 project.