feat: redesign dashboard with Fluent KPI tiles, connection strip, and devices column

- Replace LCD-style readings with a 3×2 KPI tile grid (Fluent card surfaces, 52pt values)
- Add persistent top connection strip with horizontal chips + pump name badge
- Add elapsed test timer (DispatcherTimer, mm:ss) to Test Summary card
- Restyle Test Summary and Active Alarms with Fluent brushes/iconography
- Add Devices column (CAN / K-Line / Bench tiles) between KPI grid and test/alarms
  - Enumerates attached PCAN USB channels via PCAN_ATTACHED_CHANNELS API
  - Enumerates FTDI K-Line adapters via existing FtdiInterface helpers
  - Click to connect/disconnect; confirmation dialog when session active or test running
  - Hover tint: blue = will connect, red = will disconnect; Bench row is read-only stub
- Extend ICanService with SelectedChannel + EnumerateAttachedChannels()
- Expose IKwpService.ConnectedPort for active session device tracking
- Add DeviceRow button style with MultiDataTrigger hover colour logic
- Add 30+ new localization keys (ES + EN) for KPI labels, devices, confirmations

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Views/UserControls/RelayBankView.xaml

@@ -10,13 +10,13 @@
       DataContext = RelayBankViewModel.
     -->
     <UserControl.Resources>
-        <Style x:Key="RelayToggle" TargetType="ToggleButton">
+        <Style x:Key="RelayToggle" TargetType="ToggleButton"
+               BasedOn="{StaticResource FluentStateToggle}">
             <Setter Property="Height" Value="28"/>
             <Setter Property="FontSize" Value="11"/>
             <Setter Property="FontWeight" Value="SemiBold"/>
             <Setter Property="Margin" Value="0,2,0,0"/>
             <Setter Property="Content" Value="{DynamicResource Bench.RelayOff}"/>
-            <Setter Property="Background" Value="LightGray"/>
             <Style.Triggers>
                 <Trigger Property="IsChecked" Value="True">
                     <Setter Property="Content" Value="{DynamicResource Bench.RelayOn}"/>