Filter unrelated benchmark events

[ludfjig]

Summary:

• skip benchmark workload for unrelated labels and title or body edits
• keep the required Benchmark Status and Benchmark Policy contexts on every triggered event
• queue ignored-event contexts behind active required work so they cannot mask or cancel it
• rerun policy and workload for code, base branch, and benchmarks: skip changes

Validation:

• npm run build
• workflow YAML parsing
• editor workflow diagnostics
• git diff --check
• hosted overlap: an unrelated label event arrived while the synchronize workload was active
• hosted overlap: the ignored Benchmark Status remained pending behind the active workload
• hosted overlap: the active workload and queued ignored refresh both succeeded
• hosted overlap: ignored events started no workload child jobs
• required checks: 2 successful, 0 pending, 0 failing
• final merge state: clean

Tests were not run.