feat: add AppRegistry, RootLayout, UIHandler, and UIApp classes for improved UI management

main/ui/app_registry.h

@@ -0,0 +1,39 @@
+#pragma once
+#include "ui/ui_app.h"
+#include <vector>
+
+/**
+ * @brief Registry for all available apps
+ *
+ * This singleton class maintains a list of all registered
+ * AppDescriptor instances, allowing the UIHandler or other
+ * components to query available apps.
+ */
+class AppRegistry {
+public:
+  static AppRegistry& instance() {
+    static AppRegistry registry;
+    return registry;
+  }
+
+  AppRegistry(const AppRegistry&) = delete;
+  void operator=(const AppRegistry&) = delete;
+  AppRegistry(AppRegistry&&) = delete;
+  void operator=(AppRegistry&&) = delete;
+
+
+  // Register a new app descriptor
+  // The registry takes ownership of the descriptor pointer.
+  void register_app(AppDescriptor* app_descriptor) {
+    _app_descriptors.push_back(app_descriptor);
+  }
+
+  const std::vector<AppDescriptor*>& get_app_descriptors() const {
+    return _app_descriptors;
+  }
+
+private:
+  AppRegistry() = default;
+  ~AppRegistry() = default;
+  std::vector<AppDescriptor*> _app_descriptors = {};
+};