feat: update SDK and GUI versions, add debugger protection settings

- Updated SDK_DECODER_SEMVER to "1.3.0" and GUI_SEMVER to "1.2.4" in config.ini.
- Updated MailViewer component to handle PDF already open error and improved iframe handling.
- Removed deprecated useMsgConverter setting from settings page.
- Added IsDebuggerRunning function to check for attached debuggers and quit the app if detected.
- Enhanced PDF viewer to prevent infinite loading and improved error handling.

Co-Authored-By: Laky-64 <iraci.matteo@gmail.com>

frontend/src/lib/stores/settings.svelte.ts

@@ -5,9 +5,11 @@ import { getFromLocalStorage, saveToLocalStorage } from "$lib/utils/localStorage
 const STORAGE_KEY = "emly_gui_settings";
 
 const defaults: EMLy_GUI_Settings = {
-    selectedLanguage: "en",
+    selectedLanguage: "it",
     useBuiltinPreview: true,
+    useBuiltinPDFViewer: true,
     previewFileSupportedTypes: ["jpg", "jpeg", "png"],
+    enableAttachedDebuggerProtection: true,
 };
 
 class SettingsStore {