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

include/faset/editor/editor_ui.hpp

@@ -0,0 +1,28 @@
+#pragma once
+#include <faset/editor/session.hpp>
+#include <faset/ui/ui.hpp>
+#include <memory>
+
+namespace faset::editor {
+// Owns authoring presentation only. Player execution and MCP transport stay in
+// the application.
+class EditorUI {
+  public:
+    EditorUI(Session&, render::Renderer&, const std::filesystem::path& font,
+             const std::filesystem::path& styles);
+    ~EditorUI();
+    EditorUI(const EditorUI&) = delete;
+    EditorUI& operator=(const EditorUI&) = delete;
+    void frame(const std::vector<render::Event>&);
+    const render::Snapshot& snapshot() const;
+    ui::Context& widgets();
+    const std::string& current_document() const;
+    void select_document(const std::string& document);
+    const std::string& selected_entity() const;
+    void select_entity(const std::string& entity);
+
+  private:
+    struct Impl;
+    std::unique_ptr<Impl> impl_;
+};
+} // namespace faset::editor