* feat: spill large tool results to artifacts, show tail
- Add centralized spillLargeResultToArtifact() in wrappedExecute pipeline
- Tool results exceeding 50KB saved as session artifacts via saveArtifact()
- Content truncated to tail (20KB / 500 lines) instead of head
- Truncation notice includes artifact:// reference for full output retrieval
- Skip spill when tool already saved its own artifact (bash/python/ssh)
- Update formatFullOutputReference to use action-oriented wording
* feat: per-turn token usage display on assistant messages
* fix: TS errors in output-meta truncation fields
luke
2f496efba9