1.0.0

Fix review findings: rubric-version single source + doc/anchor accuracy

- rubricVersion now has one source of truth: grading/config.json. Removed
  the redundant manifest top-level field; validate.mjs and grade.mjs both
  key off config, so a deliberate version bump can't desync them (the
  latent bug that would have failed every submission on the first bump).
- Reworded the Laguna robustness anchor everywhere (PROMPT/RUBRIC/
  methodology) to match its real runtime verdict — loads, then throws on
  the detail route (errors) — not a load crash.
- running-a-benchmark.md: the opencode grade path is two-pass; rewrote the
  Calibration section for the append-only fixed-anchor model (it still
  described the replaced co-grade / re-grade-the-whole-set approach).
- Tighter provenance validation (oneShot/autonomous/verified), dedupe
  .gitignore, skip the unused Playwright browser download in CI.