fix: hide recovered run errors

[ahamSel]

Summary

• clear transient tool errors when a run finishes successfully
• normalize historical successful runs so old recovered runs no longer display stale run-level errors
• keep failed tool steps visible in detailed traces for audit/debugging

Validation

• npm run lint
• npm run build
• npm run health
• node -c lib/agent.ts
• node -c lib/recorder.ts
• verified run_1777886071496_41xw normalizes as done with the failed click retained only in the step trace