diff --git a/.gitignore b/.gitignore
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+# Root-level artefacts only; each project has its own .gitignore.
+
+# Tool caches created when tests or scripts run from the repo root.
+/node_modules/
+
+# Working notes of the SDD orchestration (ledgers, briefs, review reports)
+# and design mockups/screenshots (~90 MB). Decisions that matter are in
+# ARCHITECTURE.md, the specs/plans under docs/ and the Gitea issues.
+/.superpowers/