chore(semantics): add v6 release gate pipeline

- Add reproducible v6 boundary, blessing, and consensus-adjudication
  corpora, plus the tiny-transformer trainer and v6 release-gate
  evaluator that gate every candidate on the deployed baselines.
- Wire consensus-label merging, product-policy anchor evaluation, and
  sealed blessing benchmark review with their pytest coverage.
- Refresh open-training corpus generation, iterative retraining runner,
  and random-holdout evaluation so v6 candidates can be benchmarked
  end-to-end.

ModelTraining/ClipboardSemantics/BlessingBenchmark/README.md

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+# Blessing benchmark review
+
+This directory contains a blind, evaluation-only review queue derived from the
+frozen comprehensive holdout. It must never be merged into training.
+
+## Review process
+
+1. Give `review-queue.jsonl` and one annotation template to each of two
+   independent human annotators.
+2. Do not give annotators `sealed-provenance.jsonl`, the other annotator's
+   answers, model predictions, or previous weak labels.
+3. Each annotator fills every `label`, `boundaryCategory`, and `confidence`
+   field in their own JSONL file.
+4. Run `finalize_blessing_benchmark.py` with distinct annotator IDs.
+5. If annotations disagree, give only `adjudication-needed.jsonl` to a third
+   reviewer and rerun the finalizer with the adjudication file.
+
+## Label
+
+Set `label` to `true` only when the author directly expresses a good wish,
+congratulation, prayer, or hope for a recipient. Third-person and self-directed
+wishes count. Requests for a blessing, quoted examples, received thanks,
+celebration descriptions, ordinary greetings, reports of someone else's wish,
+and sarcasm do not count.
+
+## Boundary categories
+
+Use one of these stable values:
+
+### Positive
+
+- `festival_or_birthday`
+- `congratulation`
+- `health_or_recovery`
+- `travel_or_safety`
+- `study_or_career`
+- `general_good_wish`
+- `third_person_or_group`
+- `spiritual_or_prayer`
+
+### Negative
+
+- `meta_request_or_template`
+- `received_thanks`
+- `quoted_or_documented`
+- `celebration_mention`
+- `ordinary_greeting`
+- `positive_language_only`
+- `reported_wish`
+- `sarcasm_or_anti_blessing`
+- `unrelated`
+
+Use `confidence` values `high`, `medium`, or `low`. Explain genuinely
+ambiguous context in `notes`.
+
+## Finalization
+
+```bash
+python3 Scripts/clipboard_semantics/finalize_blessing_benchmark.py \
+  --annotator-a-id reviewer-a \
+  --annotator-b-id reviewer-b
+```
+
+The command refuses incomplete annotation, duplicate IDs, non-boolean labels,
+invalid confidence, missing adjudication, or use of the same person as both
+annotators. The finalized benchmark is split deterministically into calibration
+and test records.