fix(pve): Fix connection issues and add more error handlings (#1081)

* feat(PVE): Added display of PVE connection loading steps

Added a detailed display of loading steps during the PVE connection process, including stages such as establishing an SSH tunnel, authentication, and data retrieval

Also optimized the sorting of PVE storage content and the logic for handling connection errors

* feat(pve): Added error handling and prompts for PVE two-factor authentication

Added error handling for PVE servers when two-factor authentication is enabled, along with relevant error types and localized prompts

* feat(PVE): Added support for PVE passwords during key-based authentication

- Added the `pvePwd` field to the `ServerCustom` model
- Added a PVE password input field to the edit page (displayed only during key-based authentication)
- Updated multilingual files to support PVE-related loading states and password prompts
- Optimized PVE connection logic to support password verification during key-based authentication

lib/generated/l10n/l10n_de.dart

@@ -538,10 +538,33 @@ class AppLocalizationsDe extends AppLocalizations {
   String get pveLoginFailed =>
       'Anmeldung fehlgeschlagen. Kann nicht mit Benutzername/Passwort aus der Serverkonfiguration angemeldet werden, um sich über Linux PAM anzumelden.';
 
+  @override
+  String get pveOtpRequired =>
+      'Two-factor authentication is enabled on this PVE server. Please enter the OTP code.';
+
   @override
   String get pveVersionLow =>
       'Diese Funktion befindet sich derzeit in der Testphase und wurde nur auf PVE 8+ getestet. Bitte verwenden Sie sie mit Vorsicht.';
 
+  @override
+  String get pveLoadingForwarding => 'Establishing SSH tunnel...';
+
+  @override
+  String get pveLoadingLogin => 'Authenticating with PVE...';
+
+  @override
+  String get pveLoadingData => 'Fetching cluster data...';
+
+  @override
+  String get pveLoadingConnect => 'Connecting...';
+
+  @override
+  String get pvePassword => 'PVE Password';
+
+  @override
+  String get pvePasswordHint =>
+      'Required when using key-based SSH authentication';
+
   @override
   String get read => 'Lesen';