feat: QO-100 beacon bulletin text display (Phase C)

Decode and show the AO-40 frame payload as text in the beacon scope window.

- RadioController.GetBeaconFrame exposes the latest 256-byte frame.
- BeaconScopeForm: poll the frame counter; on each new frame, parse the
  payload (drop trailing 2-byte CRC, printable ASCII, 64-char lines, as in
  gr-satellites qo100.parse) and append to a scrolling read-only memo.
- Window widened/heightened; constellation size capped to leave room.

Frame format verified offline against a real on-air capture: the decoder
produces the live QO-100 AMSAT bulletin text (RS errors=0).

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

RadioController.pas

@@ -49,7 +49,7 @@ interface
 uses
   Classes, SysUtils, Math,
   HPSDRProtocol, HPSDRNetwork, RadioBackend, PlutoBackend, IIOBindings,
-  WDSPEngine, AudioOutput, AudioInput, BeaconDecoder,
+  WDSPEngine, AudioOutput, AudioInput, BeaconDecoder, BeaconFEC,
   Settings, ChannelStore, FMRepeater, BoardUtils, DeviceStore;
 
 type
@@ -503,6 +503,7 @@ type
     procedure SetBeaconDecodeInvert(On_: Boolean);    // зеркальный baseband вкл/выкл
     function  BeaconDecodeInvert: Boolean;
     function  GetBeaconScope(out S: TBeaconScope): Boolean;
+    function  GetBeaconFrame(out Frame: TBeaconFrame; out RSErrors: Integer): Boolean;
 
     // Отображение / приём
     procedure SetCTun(On_: Boolean);
@@ -1473,6 +1474,11 @@ begin
   else FillChar(S, SizeOf(S), 0);
 end;
 
+function TRadioController.GetBeaconFrame(out Frame: TBeaconFrame; out RSErrors: Integer): Boolean;
+begin
+  Result := Assigned(FBeaconDec) and FBeaconDec.GetLastFrame(Frame, RSErrors);
+end;
+
 procedure TRadioController.ApplyModeFilter;
 var
   Lo, Hi, Half: Integer;