feat: Add TCP connection support and UI integration

- Implemented TCP transport service for native platforms.
- Added TCP connection screen with input fields for host and port.
- Integrated TCP connection options into the scanner and USB screens.
- Updated localization files for new TCP-related strings.
- Added tests for TCP connection flow and error handling.
- Enhanced USB screen to include TCP connection option.
- Improved layout to ensure no overflow in narrow widths for scanner and USB screens.

lib/l10n/app_localizations_sl.dart

@@ -117,6 +117,53 @@ class AppLocalizationsSl extends AppLocalizations {
   @override
   String get connectionChoiceBluetoothLabel => 'Bluetooth';
 
+  @override
+  String get connectionChoiceTcpLabel => 'TCP';
+
+  @override
+  String get tcpScreenTitle => 'Komunicirajte preko protokola TCP';
+
+  @override
+  String get tcpHostLabel => 'IP naslov';
+
+  @override
+  String get tcpHostHint => '192.168.40.10';
+
+  @override
+  String get tcpPortLabel => 'Pril';
+
+  @override
+  String get tcpPortHint => '5000';
+
+  @override
+  String get tcpStatus_notConnected => 'Vnesite končni naslov in se povežite';
+
+  @override
+  String get tcpStatus_connecting => 'Povezava z TCP koncem...';
+
+  @override
+  String tcpStatus_connectingTo(String endpoint) {
+    return 'Povezava z $endpoint...';
+  }
+
+  @override
+  String get tcpErrorHostRequired => 'Potrebna je IP-naslov.';
+
+  @override
+  String get tcpErrorPortInvalid => 'Port mora biti med 1 in 65535.';
+
+  @override
+  String get tcpErrorUnsupported =>
+      'Transport preko protokola TCP ni podprt na tej platformi.';
+
+  @override
+  String get tcpErrorTimedOut => 'Povezava TCP je presegla časovno obdobje.';
+
+  @override
+  String tcpConnectionFailed(String error) {
+    return 'Napaka pri povezavi TCP: $error';
+  }
+
   @override
   String get usbScreenTitle => 'Povežite preko USB';