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>

Services/ICanService.cs

@@ -41,6 +41,22 @@ namespace HC_APTBS.Services
         /// <summary>True when the CAN read thread is running and the channel is open.</summary>
         bool IsConnected { get; }
 
+        /// <summary>
+        /// The PCAN channel handle that will be used on the next <see cref="Connect"/> call.
+        /// Defaults to the channel supplied at construction.
+        /// Throws <see cref="System.InvalidOperationException"/> when set while <see cref="IsConnected"/> is true.
+        /// </summary>
+        TPCANHandle SelectedChannel { get; set; }
+
+        // ── Discovery ─────────────────────────────────────────────────────────────
+
+        /// <summary>
+        /// Enumerates PCAN USB channels that are physically attached to the system.
+        /// Returns an empty list if no adapters are connected or if the PCAN-Basic DLL
+        /// is unavailable. Never throws.
+        /// </summary>
+        System.Collections.Generic.IReadOnlyList<AttachedPcanChannel> EnumerateAttachedChannels();
+
         // ── Lifecycle ─────────────────────────────────────────────────────────────
 
         /// <summary>