Add configurable VFO frequency range with GHz support

- Settings > Display: new "VFO Display" control to select max frequency
  range (999 MHz / 9.999 GHz / 99.999 GHz), persisted as freq_mhz_digits
- FreqDisplay: extend digit map [0..10] to support up to 11 digit positions;
  keyboard navigation adapts to MinMhzDigits dynamically
- MainForm/LayoutTopVfoBlock: VFO panel width scales automatically with
  selected digit count using dynamic text measurement
- Web VFO: fix broken HTML (class attr not closed before data-s — wheel and
  hover were completely non-functional); rewrite fmtVfo to use variable MHz
  digit count synced from server state; fix missing </span> for .vfo-hz
- WebServer: publish freq_mhz_digits in state JSON; updated from
  ApplyFreqMhzDigits so desktop and web stay in sync
- Fix Int32 overflow on frequencies above ~2.15 GHz: CATEngine.Pad V param
  Int64, FormatFreq/FormatFreqSV Mhz var Int64 (Mhz*1000000 overflowed)

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

MainForm.pas

@@ -278,6 +278,7 @@ type
     FBandCache:      array[0..CFG_BAND_COUNT-1] of TBandSettings; // кэш диапазонов
     FDevConnected:   Boolean;            // True после первого подключения
     FLightTheme:     Boolean;            // True = светлая тема
+    FFreqMhzDigits:  Integer;            // 3=999MHz, 4=9.999GHz, 5=99.999GHz
     FCenterFreq:     Double;   // центр спектра = LO (DDC). При CTUN ON не меняется при кручении VFO
     FSpanHz:         Double;
     FSampleRate:     Integer;   // текущий DDC sample rate (Hz)
@@ -630,6 +631,7 @@ type
     function  BuildMicLineSelectByte: Byte;
     procedure ApplyVisibility(ShowSpectrum, ShowWaterfall: Boolean);
     procedure ApplyFPS(FPS: Integer);
+    procedure ApplyFreqMhzDigits(Digits: Integer);
 
   published
     // Обработчики событий формы — должны быть в published для RTTI/LFM
@@ -919,6 +921,7 @@ begin
   Result.DisplayDuplex   := FDisplayDuplex;
   Result.DisplayFPS      := FDisplayFPS;
   Result.LightTheme      := FLightTheme;
+  Result.FreqMhzDigits   := FFreqMhzDigits;
   // Audio device names
   Result.AudioOutDevice := FAudioOutDevName;
   Result.AudioInDevice  := FAudioInDevName;
@@ -1182,6 +1185,7 @@ begin
   FShowSpectrum  := True;
   FShowWaterfall := True;
   FDisplayFPS    := 60;
+  FFreqMhzDigits := 3;
   FSplitterRatio := 0.40;
   FSplitterDrag  := False;
 
@@ -1992,7 +1996,7 @@ begin
   Canvas.Font.Style := [fsBold];
   FreqDispA.Left := VFO_BTN_W + VFO_BTN_FREQ_GAP - VFO_FREQ_LEFT_PAD;
   FreqDispB.Left := VFO_B_LEFT_PAD + VFO_BTN_W + VFO_BTN_FREQ_GAP - VFO_FREQ_LEFT_PAD;
-  FreqTextW  := Canvas.TextWidth('000.000.000');
+  FreqTextW  := Canvas.TextWidth(StringOfChar('0', Max(3, FFreqMhzDigits)) + '.000.000');
   NeedFreqAW := FreqDispA.Left + FreqTextW + VFO_FREQ_LEFT_PAD + VFO_FREQ_RIGHT_PAD;
   NeedFreqBW := FreqDispB.Left + FreqTextW + VFO_FREQ_LEFT_PAD + VFO_FREQ_RIGHT_PAD;
   TopVfoAW := NeedFreqAW;
@@ -2448,12 +2452,13 @@ end;
 
 function TMainForm.FormatFreq(Hz: Double): string;
 var
-  Mhz, KHz, Rest: Integer;
+  Mhz: Int64;
+  KHz, Rest: Integer;
 begin
   Mhz  := Trunc(Hz / 1000000);
   KHz  := Trunc((Hz - Mhz * 1000000) / 1000);
   Rest := Trunc(Hz) mod 1000;
-  Result := Format('%3d.%3.3d.%3.3d', [Mhz, KHz, Rest]);
+  Result := Format('%d.%3.3d.%3.3d', [Mhz, KHz, Rest]);
 end;
 
 procedure TMainForm.UpdateVfoDisplay;
@@ -3568,6 +3573,7 @@ begin
   if BtnDUP <> nil then StyleButton(BtnDUP, FDisplayDuplex);
   if G_Settings.DisplayFPS > 0 then
     ApplyFPS(G_Settings.DisplayFPS);
+  ApplyFreqMhzDigits(EnsureRange(G_Settings.FreqMhzDigits, 3, 5));
   // Настройки дисплея и сетки
   if G_Settings.FFTSize > 0 then
   begin
@@ -6116,6 +6122,21 @@ begin
     FDSPEngine.SetDisplayFPS(FPS);
 end;
 
+procedure TMainForm.ApplyFreqMhzDigits(Digits: Integer);
+const
+  MaxFreqs: array[3..5] of Int64 = (999999999, 9999999999, 99999999999);
+begin
+  Digits := EnsureRange(Digits, 3, 5);
+  FFreqMhzDigits := Digits;
+  FreqDispA.MinMhzDigits := Digits;
+  FreqDispB.MinMhzDigits := Digits;
+  FreqDispA.MaxFreq := MaxFreqs[Digits];
+  FreqDispB.MaxFreq := MaxFreqs[Digits];
+  if Assigned(FWebServer) then
+    FWebServer.FreqMhzDigits := Digits;
+  LayoutTopVfoBlock;
+end;
+
 procedure TMainForm.BtnSettingsClick(Sender: TObject);
 var
   SF: TSettingsForm;
@@ -6133,8 +6154,9 @@ begin
     SF.OnFPSChange        := ApplyFPS;
     SF.OnPAChange         := OnPASettingsChange;
     SF.OnCATChange        := OnCATSettingsChange;
-    SF.OnThemeChange      := SetLightTheme;
-    SF.OnTXChange         := OnTXSettingsChange;
+    SF.OnThemeChange           := SetLightTheme;
+    SF.OnFreqMhzDigitsChange   := ApplyFreqMhzDigits;
+    SF.OnTXChange              := OnTXSettingsChange;
     SF.OnAlexChange       := OnAlexSettingsChange;
     SF.OnXvtrChange       := OnXvtrSettingsChange;
   end;
@@ -6158,6 +6180,7 @@ begin
   SF.LoadVisibility(FShowSpectrum, FShowWaterfall);
   SF.LoadFPS(FDisplayFPS);
   SF.LoadLightTheme(FLightTheme);
+  SF.LoadFreqMhzDigits(FFreqMhzDigits);
   // Загружаем текущие значения
   if FWDSPReady then
     SF.LoadValues(