Add supply current display for Orion MkII (Board 5)

UserADC1 (bytes 55-56) carries current sensor data on the ANAN-8000DLE.
Formula from Thetis: amps = ((adc/4095 * 5000) - 360) / 120 (Voff=360mV,
Sens=120mV/A). Status bar now shows "Supply: 13.8V / 2.3A | PLL OK"
when current is available.

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

HPSDRProtocol.pas

@@ -392,6 +392,10 @@ function PhaseWordToFreq(PhaseWord: LongWord): Double;
 // Returns -1.0 if the board has no supply voltage measurement.
 function ADCToSupplyVolts(RawADC: Word; BoardType: Integer): Double;
 
+// Convert raw ADC value to supply current in Amps (Board 5 / Orion MkII only)
+// Uses UserADC1 (bytes 55-56). Returns -1 for unsupported boards.
+function ADCToSupplyCurrent(RawADC: Word; BoardType: Integer): Double;
+
 // Convert raw ADC value to RF power in Watts (ANAN-100)
 function ADCToWatts100(RawADC: Word): Double;
 
@@ -454,6 +458,19 @@ begin
   end;
 end;
 
+function ADCToSupplyCurrent(RawADC: Word; BoardType: Integer): Double;
+begin
+  // Board 5 (Orion MkII): UserADC1, Vref=5V → mV = adc/4095*5000.
+  // Current sensor: Voff=360mV, Sens=120mV/A (Thetis defaults, ACS712-style).
+  // Formula: amps = (mV - Voff) / Sens.
+  if BoardType = 5 then
+  begin
+    Result := ((RawADC / 4095.0) * 5000.0 - 360.0) / 120.0;
+    if Result < 0.0 then Result := 0.0;
+  end else
+    Result := -1.0;
+end;
+
 function ADCToWatts100(RawADC: Word): Double;
 var
   V: Double;