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/.gitignore

@@ -25,3 +25,6 @@ vite.config.ts.timestamp-*
 # Paraglide
 src/lib/paraglide
 project.inlang/cache/
+
+# Wails
+/src/lib/wailsjs