Add Shardok clang-tidy CI gate (#8189)

scripts/check_shardok_clang_tidy.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+# Runs the curated Shardok clang-tidy gate used by CI.
+#
+# This intentionally checks representative files instead of the whole C++ tree.
+# Keep this list low-noise; expand it as cleanup PRs make more areas tidy-clean.
+
+set -euo pipefail
+
+repo_root="$(git rev-parse --show-toplevel)"
+
+files=(
+    "src/main/cpp/net/eagle0/shardok/library/ActionCost.hpp"
+    "src/main/cpp/net/eagle0/shardok/library/CombatDamage.hpp"
+)
+
+"$repo_root/scripts/run-clang-tidy.sh" --verify-config
+
+"$repo_root/scripts/run-clang-tidy.sh" --quiet --warnings-as-errors="*" "${files[@]}" -- -I"$repo_root" -std=c++23