Add about menu service boundary

src/app_core/about_menu.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "foundation/result.h"
+
 #include <string>
 
 namespace pp::app {
@@ -31,6 +33,17 @@ struct AboutMenuPlan {
     int performance_updates_per_iteration = 0;
 };
 
+class AboutMenuServices {
+public:
+    virtual ~AboutMenuServices() = default;
+
+    virtual void show_user_manual() = 0;
+    virtual void show_about_dialog() = 0;
+    virtual void show_whats_new_dialog() = 0;
+    virtual void trigger_crash_test() = 0;
+    virtual void run_performance_test(const AboutMenuPlan& plan) = 0;
+};
+
 [[nodiscard]] inline AboutMenuPlan plan_about_menu_command(
     AboutMenuCommand command,
     int version_major,
@@ -83,4 +96,31 @@ struct AboutMenuPlan {
     return plan;
 }
 
+[[nodiscard]] inline pp::foundation::Status execute_about_menu_plan(
+    const AboutMenuPlan& plan,
+    AboutMenuServices& services)
+{
+    switch (plan.action) {
+    case AboutMenuAction::show_user_manual:
+        services.show_user_manual();
+        return pp::foundation::Status::success();
+    case AboutMenuAction::show_about_dialog:
+        services.show_about_dialog();
+        return pp::foundation::Status::success();
+    case AboutMenuAction::show_whats_new_dialog:
+        services.show_whats_new_dialog();
+        return pp::foundation::Status::success();
+    case AboutMenuAction::trigger_crash_test:
+        services.trigger_crash_test();
+        return pp::foundation::Status::success();
+    case AboutMenuAction::run_performance_test:
+        services.run_performance_test(plan);
+        return pp::foundation::Status::success();
+    case AboutMenuAction::no_op_unavailable:
+        return pp::foundation::Status::success();
+    }
+
+    return pp::foundation::Status::invalid_argument("unknown about menu action");
+}
+
 }