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>

Models/AttachedPcanChannel.cs

@@ -0,0 +1,13 @@
+using Peak.Can.Basic;
+using TPCANHandle = System.UInt16;
+
+namespace HC_APTBS.Models
+{
+    /// <summary>
+    /// Describes a PCAN USB channel that is physically attached to the system,
+    /// as reported by the PCAN-Basic <c>PCAN_ATTACHED_CHANNELS</c> API call.
+    /// </summary>
+    /// <param name="Handle">PCAN channel handle (e.g. <c>PCANBasic.PCAN_USBBUS1</c>).</param>
+    /// <param name="DisplayName">Human-readable name returned by the PCAN driver (e.g. "PCAN-USB (1)").</param>
+    public sealed record AttachedPcanChannel(TPCANHandle Handle, string DisplayName);
+}