v0.19.0

T1-5.1: the benchmark re-baselined on the current model tier, with quality as an artifact.

Added

• evals/rubric.md — the five-dimension, two-lens (inspection + mutation) quality rubric as
  a persisted artifact, and evals/quality/ scoring files: one for the T1-5.1 campaign
  (claude-fable-5-1) and one applied retroactively to the verified claude-fable-5
  workspaces. Quality claims now point at a file, not a transcript.
• T1-5.1 campaign conclusion in evals/results.md: bare $1.41 / Standard $3.33 (2.4×,
  evaluator on) / Deep $5.97 (4.2×) on 5.1; quality parity across arms on both tiers (72/72/71
  vs 68/70/68 of 75); the closeout evaluator challenged 3 of 6 plugin closeouts, twice on a
  real cross-surface parity defect.

Changed

• Eval fixture enables closeout-evaluator: on, so the opt-in evaluator's cost lands in the
  plugin rows instead of being priced at zero (test asserts the key).
• run-eval.sh default model is claude-fable-5-1; rows before 2026-09-04 ran
  claude-fable-5 and stay comparable only among themselves (D-015). Dry-run test pins the default.
• README "Self-measuring" quotes the 5.1 numbers.