Add clang-tidy runner script (#7347)

scripts/run-clang-tidy.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+# Runs the repository-pinned clang-tidy binary from the workspace root.
+#
+# Bazel's `run` command executes clang-tidy from its runfiles tree, which makes
+# workspace-relative source paths and .clang-tidy discovery fail. This wrapper
+# builds the tool and then invokes the produced binary directly.
+
+set -e
+
+export PATH="/opt/homebrew/bin:/usr/local/bin:$PATH"
+
+repo_root="$(git rev-parse --show-toplevel)"
+
+if [ "$#" -eq 0 ]; then
+    echo "Usage: scripts/run-clang-tidy.sh [clang-tidy args] <files> [-- <compiler args>]"
+    echo ""
+    echo "Examples:"
+    echo "  scripts/run-clang-tidy.sh --verify-config"
+    echo "  scripts/run-clang-tidy.sh src/main/cpp/net/eagle0/shardok/library/CombatDamage.hpp -- -I$repo_root -std=c++23"
+    exit 2
+fi
+
+bazel build @llvm_toolchain//:clang-tidy
+
+bazel_bin="$(bazel info bazel-bin)"
+clang_tidy="$bazel_bin/external/toolchains_llvm++llvm+llvm_toolchain/clang-tidy"
+
+if [ ! -x "$clang_tidy" ]; then
+    echo "Unable to find clang-tidy binary at $clang_tidy"
+    exit 1
+fi
+
+"$clang_tidy" --config-file="$repo_root/.clang-tidy" "$@"