add base-apps with manifests, layout system, and testing documentation

- Rename test-apps to base-apps with proper manifest.json for each app
- Add is_system_app flag to app discovery and Lua API
- Fix icon path resolution for /system/icons/ paths
- Add layout.lua and layout.rcss for reusable UI components
- Update home screen to dynamically load all apps from manifests
- Update all app RML files to use layout components
- Comprehensive testing framework documentation with JSON action format
- Add tests/ directory structure for automated UI testing

designer/src/app_discovery.cpp

@@ -68,6 +68,7 @@ bool AppDiscovery::LoadAppManifest(const std::string& app_directory, AppInfo& in
         info.version = j.value("version", "1.0.0");
         info.icon = j.value("icon", "icon.tga");
         info.description = j.value("description", "");
+        info.is_system_app = j.value("is_system_app", false);
 
         // Normalize path separators
         info.app_path = app_directory;

designer/src/app_discovery.h

@@ -11,13 +11,20 @@ struct AppInfo {
     std::string name;         // Display name
     std::string version;      // Version string
     std::string entry;        // Entry point (e.g., "main.rml")
-    std::string icon;         // Icon filename (e.g., "icon.tga")
+    std::string icon;         // Icon filename (e.g., "icon.tga") or path (e.g., "/system/icons/phone.tga")
     std::string description;  // App description
     std::string app_path;     // Full path to app directory
+    bool is_system_app = false;  // True for system apps (com.mosis.*)
 
     // Computed paths
     std::string GetEntryPath() const { return app_path + "/" + entry; }
-    std::string GetIconPath() const { return app_path + "/" + icon; }
+    std::string GetIconPath() const {
+        // If icon starts with /, it's an absolute/system path - don't prepend app_path
+        if (!icon.empty() && icon[0] == '/') {
+            return icon;
+        }
+        return app_path + "/" + icon;
+    }
 };
 
 class AppDiscovery {