add simulator mode to desktop designer for testing apps

- Add --simulator flag to launch home screen showing discovered apps
- Create app discovery system to scan test-apps/ directory
- Build simulator home screen with dark phone-like UI
- Add Lua API: simulator.launchApp, simulator.goHome, simulator.getApps
- ESC key returns to home when inside an app
- Apps displayed with icons in grid layout

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

designer/src/app_discovery.cpp

@@ -0,0 +1,91 @@
+// D:\Dev\Mosis\MosisService\designer\src\app_discovery.cpp
+#include "app_discovery.h"
+#include <nlohmann/json.hpp>
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+
+namespace fs = std::filesystem;
+using json = nlohmann::json;
+
+namespace mosis {
+
+std::vector<AppInfo> AppDiscovery::DiscoverApps(const std::string& apps_directory) {
+    std::vector<AppInfo> apps;
+
+    if (!fs::exists(apps_directory) || !fs::is_directory(apps_directory)) {
+        std::cerr << "AppDiscovery: Directory not found: " << apps_directory << std::endl;
+        return apps;
+    }
+
+    std::cout << "AppDiscovery: Scanning " << apps_directory << std::endl;
+
+    for (const auto& entry : fs::directory_iterator(apps_directory)) {
+        if (!entry.is_directory()) continue;
+
+        std::string app_dir = entry.path().string();
+        AppInfo info;
+
+        if (LoadAppManifest(app_dir, info)) {
+            apps.push_back(std::move(info));
+            std::cout << "AppDiscovery: Found app '" << apps.back().name
+                      << "' (" << apps.back().id << ")" << std::endl;
+        }
+    }
+
+    std::cout << "AppDiscovery: Found " << apps.size() << " apps" << std::endl;
+    return apps;
+}
+
+bool AppDiscovery::LoadAppManifest(const std::string& app_directory, AppInfo& info) {
+    fs::path manifest_path = fs::path(app_directory) / "manifest.json";
+
+    if (!fs::exists(manifest_path)) {
+        return false;
+    }
+
+    try {
+        std::ifstream file(manifest_path);
+        if (!file.is_open()) {
+            std::cerr << "AppDiscovery: Cannot open " << manifest_path << std::endl;
+            return false;
+        }
+
+        json j;
+        file >> j;
+
+        // Required fields
+        if (!j.contains("id") || !j.contains("name") || !j.contains("entry")) {
+            std::cerr << "AppDiscovery: Missing required fields in " << manifest_path << std::endl;
+            return false;
+        }
+
+        info.id = j["id"].get<std::string>();
+        info.name = j["name"].get<std::string>();
+        info.entry = j["entry"].get<std::string>();
+
+        // Optional fields
+        info.version = j.value("version", "1.0.0");
+        info.icon = j.value("icon", "icon.tga");
+        info.description = j.value("description", "");
+
+        // Normalize path separators
+        info.app_path = app_directory;
+        std::replace(info.app_path.begin(), info.app_path.end(), '\\', '/');
+
+        // Verify entry file exists
+        fs::path entry_path = fs::path(app_directory) / info.entry;
+        if (!fs::exists(entry_path)) {
+            std::cerr << "AppDiscovery: Entry file not found: " << entry_path << std::endl;
+            return false;
+        }
+
+        return true;
+    }
+    catch (const std::exception& e) {
+        std::cerr << "AppDiscovery: Error parsing " << manifest_path << ": " << e.what() << std::endl;
+        return false;
+    }
+}
+
+} // namespace mosis

designer/src/app_discovery.h

@@ -0,0 +1,32 @@
+// D:\Dev\Mosis\MosisService\designer\src\app_discovery.h
+#pragma once
+
+#include <string>
+#include <vector>
+
+namespace mosis {
+
+struct AppInfo {
+    std::string id;           // e.g., "com.mosis.sandbox-test"
+    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 description;  // App description
+    std::string app_path;     // Full path to app directory
+
+    // Computed paths
+    std::string GetEntryPath() const { return app_path + "/" + entry; }
+    std::string GetIconPath() const { return app_path + "/" + icon; }
+};
+
+class AppDiscovery {
+public:
+    // Scan a directory for apps (folders with manifest.json)
+    static std::vector<AppInfo> DiscoverApps(const std::string& apps_directory);
+
+    // Load a single app's manifest
+    static bool LoadAppManifest(const std::string& app_directory, AppInfo& info);
+};
+
+} // namespace mosis