Implement Vulkan Graphics Backend and Interfaces

- Added VulkanGraphicsBackend class for Vulkan rendering implementation.
- Created IGraphicsBackend interface for abstracted rendering operations.
- Introduced GraphicsConfig structure for graphics service configuration.
- Updated graphics_types.hpp with new configuration options.
- Implemented Vulkan backend initialization, device management, and rendering methods.
- Added tests for GXM Graphics Backend to validate functionality.
- Refactored existing graphics service interface to support backend-agnostic design.

docs/CONFIG_SELECTOR.md

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+# Config Selector Integration Guide
+
+## Overview
+The config selector provides a Lua-based GUI for selecting JSON configuration files at runtime. It automatically scans the `config/` directory for `.json` files and presents them in a navigable list.
+
+## Files Created
+- `scripts/config_selector.lua` - Main config selector implementation
+- `scripts/config_selector_demo.lua` - Demo showing usage patterns
+
+## Usage in C++ Application
+
+### 1. Include in Build System
+Add the config selector to your CMakeLists.txt or build system to ensure it's packaged with the application.
+
+### 2. Integration Points
+
+#### Startup Flow
+```cpp
+// In main.cpp or app initialization
+#ifdef ENABLE_VITA
+    // Vita: Always run config selector by default (no command line available)
+    runConfigSelector();
+#else
+    // Desktop: Check command line arguments
+    if (command_line_has("--select-config")) {
+        runConfigSelector();
+    } else if (command_line_has("--config")) {
+        // Load specific config
+        std::string configPath = getCommandLineArg("--config");
+        loadConfig(configPath);
+    } else {
+        // Default behavior - load default config
+        loadConfig("config/default.json");
+    }
+#endif
+```
+
+#### Config Selector Function
+```cpp
+void runConfigSelector() {
+    // Initialize Lua state
+    lua_State* L = luaL_newstate();
+    luaL_openlibs(L);
+
+    // Load GUI bindings
+    bindGuiFunctions(L);
+
+    // Load config selector script
+    if (luaL_dofile(L, "scripts/config_selector.lua") != LUA_OK) {
+        std::cerr << "Failed to load config selector: " << lua_tostring(L, -1) << std::endl;
+        return;
+    }
+
+    // Set Vita mode if building for Vita
+    #ifdef ENABLE_VITA
+    lua_getglobal(L, "setVitaMode");
+    if (lua_isfunction(L, -1)) {
+        lua_call(L, 0, 0);
+    }
+    #endif
+
+    // Main selector loop
+    bool finished = false;
+    while (!finished && !windowShouldClose()) {
+        // Update input state
+        updateLuaInputState(L);
+
+        // Call selector update
+        lua_getglobal(L, "update");
+        lua_call(L, 0, 0);
+
+        // Check if finished
+        lua_getglobal(L, "isFinished");
+        lua_call(L, 0, 1);
+        finished = lua_toboolean(L, -1);
+        lua_pop(L, 1);
+
+        // Render
+        render();
+
+        // Small delay to prevent busy loop
+        std::this_thread::sleep_for(std::chrono::milliseconds(16));
+    }
+
+    // Get selected config
+    if (finished) {
+        lua_getglobal(L, "getSelectedConfig");
+        lua_call(L, 0, 1);
+
+        if (lua_istable(L, -1)) {
+            // Extract config path
+            lua_getfield(L, -1, "path");
+            const char* configPath = lua_tostring(L, -1);
+
+            if (configPath) {
+                std::cout << "Selected config: " << configPath << std::endl;
+                // Restart application with selected config
+                restartApplication(configPath);
+            }
+            lua_pop(L, 1);
+        }
+        lua_pop(L, 1);
+    }
+
+    lua_close(L);
+}
+```
+
+#### Lua Bindings Required
+The config selector expects these Lua bindings from C++:
+
+```cpp
+// File system functions
+lua_register(L, "file_exists", lua_file_exists);
+lua_register(L, "list_directory", lua_list_directory);
+
+// JSON loading
+lua_register(L, "load_json_config", lua_load_json_config);
+
+// GUI functions (from existing gui.lua integration)
+lua_register(L, "newContext", lua_gui_new_context);
+lua_register(L, "newInputState", lua_gui_new_input_state);
+lua_register(L, "drawRect", lua_gui_draw_rect);
+lua_register(L, "drawRectOutline", lua_gui_draw_rect_outline);
+lua_register(L, "drawText", lua_gui_draw_text);
+
+// Logging
+lua_register(L, "log_trace", lua_log_trace);
+```
+
+### 3. Command Line Options (Desktop Only)
+On desktop platforms, add support for these command line options:
+
+```bash
+# Run config selector
+./myapp --select-config
+
+# Load specific config
+./myapp --config config/vita_gui_runtime.json
+
+# Default behavior (no args)
+./myapp  # loads default config
+```
+
+**Note**: Vita builds do not support command line options since the Vita has no command line interface. The config selector runs automatically on Vita.
+
+### 4. Vita-Specific Considerations
+- **Default Behavior**: Config selector runs automatically on Vita (no command line available)
+- Window size should be set to Vita resolution: 960x544
+- Touch input is supported via mouse simulation
+- Config files are automatically filtered to show both desktop and Vita variants
+
+### 5. Error Handling
+```cpp
+try {
+    runConfigSelector();
+} catch (const std::exception& e) {
+    std::cerr << "Config selector failed: " << e.what() << std::endl;
+    // Fall back to default config
+    loadConfig("config/default.json");
+}
+```
+
+## Config File Format
+The selector expects JSON files with optional launcher metadata:
+
+```json
+{
+    "launcher": {
+        "description": "Human-readable description of this config"
+    },
+    "app": {
+        // Application-specific settings
+    }
+}
+```
+
+## Testing
+Run the demo script to verify functionality:
+```bash
+lua scripts/config_selector_demo.lua
+```
+
+## Future Enhancements
+- Add search/filter functionality
+- Support for config categories/groups
+- Preview screenshots for configs
+- Keyboard shortcuts for quick selection