Run the review auto-merge gate in shadow mode — Stage 4 calibration (#148)

Records the would-auto-merge decision (verdict block, run notice, action
output) without acting on it. Part of Stage 4 of the human-review
optimisation program, QuantEcon/project-translation#15; merging starts
this edition's calibration window.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

Author: mmcky

.github/workflows/review-translations.yml

@@ -51,5 +51,9 @@ jobs:
           source-language: en
           target-language: fa
           docs-folder: lectures
+          # Stage 4 shadow calibration (QuantEcon/project-translation#15): records
+          # the would-auto-merge decision in the verdict block, a run notice and an
+          # output — and acts on none of them. Routing and labels are unchanged.
+          auto-merge-mode: shadow
           anthropic-api-key: ${{ secrets.ANTHROPIC_API_KEY }}
           github-token: ${{ secrets.GITHUB_TOKEN }}