Add optional Lua scripting module, examples, and validation

include/faset/scripting/project.hpp

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <filesystem>
+#include <map>
+#include <string>
+#include <vector>
+
+namespace faset::scripting {
+
+// Immutable source snapshot. Keys and entries are project-relative UTF-8 paths.
+// Only Lua files below Scripts are accepted; loading never follows symlinks.
+struct LuaProject {
+    std::vector<std::string> scripts;
+    std::map<std::string, std::string> sources;
+    std::string fingerprint;
+    bool enabled() const noexcept {
+        return !scripts.empty();
+    }
+};
+
+// project.faset.json: scripting.lua.scripts = ["Scripts/player.lua", ...].
+// An absent Lua declaration is a C++-only project.
+LuaProject loadLuaProject(const std::filesystem::path& projectRoot);
+
+// Writes the captured sources, not live files. The caller owns the target manifest.
+void writeLuaSources(const LuaProject& project, const std::filesystem::path& targetRoot);
+
+} // namespace faset::scripting