feat: Pluto board name + hardware telemetry in status bar

- Status bar / web now show Pluto/LibreSDR model + serial instead of
  "Unknown Board" (BoardDisplayName in controller; UI just renders it).
- Field 3 shows AD936x chip temperature + RX RSSI for Pluto (no PA →
  Supply only for openHPSDR). Polled via backend.ReadTelemetry (~2 Hz),
  filtered for sensor glitches (plausibility window + slew-limit, with
  anti-stick) — fixes rare bogus -15°C readings.
- Add libiio binding iio_channel_attr_read_double.
- Remove stale root pluto_integration.MD (superseded by
  doc/PLUTO_INTEGRATION_PLAN.md).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

WebAdapter.pas

@@ -19,7 +19,7 @@ interface
 
 uses
   Classes, SysUtils,
-  RadioController, WebServer, WDSPEngine, HPSDRNetwork, HPSDRProtocol, BoardUtils, Settings;
+  RadioController, WebServer, WDSPEngine, HPSDRNetwork, HPSDRProtocol, RadioBackend, BoardUtils, Settings;
 
 type
   // UI/оркестрационные операции, которые адаптер дёргает у хозяина (пока не
@@ -394,7 +394,7 @@ begin
   begin
     if FController.FRunning then StatusText := 'Running'
     else                        StatusText := 'Connected';
-    BoardText := 'Board: ' + BoardTypeName(FController.FNetwork.Device.BoardType);
+    BoardText := 'Board: ' + FController.BoardDisplayName;
     IPText    := 'IP: ' + FController.FNetwork.Device.IPAddress;
   end
   else
@@ -414,7 +414,20 @@ begin
     if FController.FLastPLLLock then PLLText := 'PLL OK'
     else                            PLLText := 'PLL?';
 
-    if not BoardSupportsSupplyVoltage(FController.FNetwork.Device.BoardType) then
+    if FController.IsPluto then
+    begin
+      // Pluto: нет PA/supply — температура чипа + RSSI приёмника (telemetry-поле).
+      SupplyText := '';
+      if FController.FLastPlutoTempC > TELEMETRY_NONE then
+        SupplyText := Format('Temp %.0fC', [FController.FLastPlutoTempC]);
+      if FController.FLastPlutoRSSIdB > TELEMETRY_NONE then
+      begin
+        if SupplyText <> '' then SupplyText := SupplyText + '  ';
+        SupplyText := SupplyText + Format('RSSI %.0fdB', [FController.FLastPlutoRSSIdB]);
+      end;
+      if SupplyText = '' then SupplyText := 'Pluto --';
+    end
+    else if not BoardSupportsSupplyVoltage(FController.FNetwork.Device.BoardType) then
       SupplyText := 'Supply n/a'
     else if FController.FLastSupplyV >= 0 then
     begin