chore(translate): restore sync-translations script

Author: sunnylqm

scripts/sync-translations.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Print candidate cndocs files that likely need translation sync
+# Strategy:
+# 1) Compare upstream/main vs local production for docs/*.md
+# 2) Map changed docs/<name>.md -> cndocs/<name>.md when target exists
+# 3) Output unique, sorted cndocs paths (one per line)
+
+REPO_ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$REPO_ROOT"
+
+# Ensure upstream exists
+if ! git remote get-url upstream >/dev/null 2>&1; then
+  echo "ERROR: missing upstream remote" >&2
+  exit 2
+fi
+
+git fetch upstream --quiet
+
+# Changed docs files between production and upstream/main
+changed_docs=$(git diff --name-only production..upstream/main -- 'docs/*.md' || true)
+
+if [ -z "${changed_docs}" ]; then
+  exit 0
+fi
+
+while IFS= read -r f; do
+  [ -z "$f" ] && continue
+  name="${f#docs/}"
+  target="cndocs/${name}"
+  if [ -f "$target" ]; then
+    echo "$target"
+  fi
+done <<< "$changed_docs" | sort -u