gsxdsm
c69d384e67
perf(test): add timing telemetry, cold-start probe, and baseline snapshot
- ci-test-shard.mjs: --write-timings aggregation into scripts/test-timings.json (bucketed, newer-snapshot-protected, corrupt-shard tolerant) and --cold-start-probe; CI shard invocations emit vitest json timings
- test-changed.mjs: structured mode/reason telemetry line (+ --print-mode)
- pr-checks.yml: upload per-shard timing artifacts
- baseline: docs/test-speed-baseline-2026-06-03.md (core 41s, engine 179s, cli 49s; cold-start ~1.3-1.8s/process => U8 gate: worthwhile-not-urgent)