Checkpoint 2: integrate native Editor, MCP, gameplay builds and standalone export

include/faset/editor/build_service.hpp

@@ -0,0 +1,55 @@
+#pragma once
+#include <faset/core/json.hpp>
+#include <filesystem>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace faset::editor {
+struct BuildConfig {
+    std::filesystem::path project_root;
+    std::filesystem::path engine_root;
+    std::filesystem::path build_directory;
+    std::filesystem::path cache_root;
+    // Separate CMake caches prevent an export from changing the active development build.
+    std::string configuration{"Debug"};
+    std::string export_configuration{"Release"};
+    std::string cmake{"cmake"};
+    std::string generator{"Ninja"};
+    std::vector<std::string> configure_arguments;
+};
+struct JobStatus {
+    std::string id, kind, state{"queued"}, stage{"queued"};
+    double progress{};
+    std::string log, error;
+    Json result = Json::object();
+    bool finished() const {
+        return state == "succeeded" || state == "failed" || state == "cancelled";
+    }
+    Json json() const;
+};
+// One serialized build/cook worker per project. GUI and MCP use the same service.
+// Input scenes must be resolved authoring snapshots, independent of live runtime state.
+class BuildService {
+  public:
+    explicit BuildService(BuildConfig);
+    ~BuildService();
+    BuildService(const BuildService&) = delete;
+    BuildService& operator=(const BuildService&) = delete;
+    void scaffold(const std::string& name, int dimension);
+    std::string start_build();
+    std::string start_cook(Json resolved_scene);
+    // Publishes output/generations/<id>; current.json changes only after all validation succeeds.
+    std::string start_export(Json resolved_scene, const std::filesystem::path& output_directory);
+    JobStatus job(const std::string& id) const;
+    std::vector<JobStatus> jobs() const;
+    void cancel(const std::string& id);
+    JobStatus wait(const std::string& id);
+    const BuildConfig& config() const;
+
+  private:
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+};
+void write_cooked_scene(const std::filesystem::path& path, const Json& resolved_scene);
+} // namespace faset::editor