feat: implement self-signed certificate support in API and UI

- Added support for self-signed TLS certificates in the ApiService, allowing configuration based on server settings.
- Introduced a toggle in the ServerConnectionPage to enable or disable trusting self-signed certificates.
- Updated localization files to include new strings for self-signed certificate settings in multiple languages.
- Enhanced the OptimizedStorageService to manage trusted servers based on user preferences for self-signed certificates.
- Improved error handling and logging throughout the affected services to ensure clarity and maintainability.

lib/l10n/app_localizations_en.dart

@@ -754,6 +754,13 @@ class AppLocalizationsEn extends AppLocalizations {
   String get customHeadersDescription =>
       'Add custom HTTP headers for authentication, API keys, or special server requirements.';
 
+  @override
+  String get allowSelfSignedCertificates => 'Trust self-signed certificates';
+
+  @override
+  String get allowSelfSignedCertificatesDescription =>
+      'Accept this server\'s TLS certificate even if it is self-signed. Enable only for servers you trust.';
+
   @override
   String get headerNameEmpty => 'Header name cannot be empty';