chore(ci): add local token drift check script

- Standalone script complementing the CI token-drift job
- Supports --fix mode to regenerate and stage changes
- Run: bash scripts/check-token-drift.sh

scripts/check-token-drift.sh

@@ -0,0 +1,79 @@
+#!/usr/bin/env bash
+# check-token-drift.sh — Verify generated design token files are up to date.
+#
+# Regenerates all token outputs from the canonical bytelyst.tokens.json
+# and diffs them against the committed files. Non-zero exit if any drift.
+#
+# Usage:
+#   bash scripts/check-token-drift.sh        # check for drift
+#   bash scripts/check-token-drift.sh --fix  # regenerate and stage changes
+
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+TOKENS_DIR="$REPO_ROOT/packages/design-tokens"
+GENERATED_DIR="$TOKENS_DIR/generated"
+
+FIX=false
+if [[ "${1:-}" == "--fix" ]]; then
+  FIX=true
+fi
+
+echo "🔍 Checking design token drift..."
+
+# 1. Snapshot current generated files
+TMPDIR=$(mktemp -d)
+trap 'rm -rf "$TMPDIR"' EXIT
+
+if [ -d "$GENERATED_DIR" ]; then
+  cp -r "$GENERATED_DIR" "$TMPDIR/before"
+else
+  mkdir -p "$TMPDIR/before"
+fi
+
+# 2. Regenerate tokens
+echo "   Regenerating tokens from bytelyst.tokens.json..."
+cd "$TOKENS_DIR"
+if [ -f "package.json" ] && grep -q '"generate"' package.json; then
+  npx tsx scripts/generate.ts 2>/dev/null || {
+    echo "⚠️  Token generation script failed — skipping drift check"
+    exit 0
+  }
+else
+  echo "⚠️  No generate script found in packages/design-tokens — skipping"
+  exit 0
+fi
+
+# 3. Snapshot regenerated output
+cp -r "$GENERATED_DIR" "$TMPDIR/after"
+
+# 4. Diff
+DIFF_OUTPUT=$(diff -rq "$TMPDIR/before" "$TMPDIR/after" 2>/dev/null || true)
+
+if [ -z "$DIFF_OUTPUT" ]; then
+  echo "✅ No token drift detected — generated files are up to date."
+  exit 0
+fi
+
+echo ""
+echo "❌ Token drift detected! The following files are out of date:"
+echo ""
+echo "$DIFF_OUTPUT" | while IFS= read -r line; do
+  # Extract just the relative path
+  file=$(echo "$line" | sed "s|.*$TMPDIR/before/||; s|.*$TMPDIR/after/||; s| differ||; s| and .*||")
+  echo "   - generated/$file"
+done
+
+if $FIX; then
+  echo ""
+  echo "🔧 --fix mode: staging regenerated token files..."
+  cd "$REPO_ROOT"
+  git add "$GENERATED_DIR"
+  echo "✅ Regenerated files staged. Commit and push to fix drift."
+  exit 0
+else
+  echo ""
+  echo "Run 'bash scripts/check-token-drift.sh --fix' to regenerate and stage."
+  echo "Or: cd packages/design-tokens && npx tsx scripts/generate.ts"
+  exit 1
+fi