feat: unify band plan across desktop + web UIs

Web band selector was hardcoded to the HF plan, so on Pluto it showed
160m..6m instead of the VHF/UHF plan and highlighted the wrong entry
(band switching itself already worked: web sends idx, controller maps it
via the IsPluto plan). Mirror the sample-rate unification.

Single source of truth = BoardUtils -> controller:
- BoardUtils: TBandInfo/TBandPlanArray + BuildBandPlan(Pluto).
- TRadioController.BandPlan returns BuildBandPlan(IsPluto).

Both UIs derive from it:
- Desktop already plan-aware (RelabelBands + RestoreBand) - unchanged.
- Web: WebServer.SetBands + "bands" in state JSON; hosts push
  BandPlan on connect/startup; JS builds the band selector from
  state.bands (BAND_N/BAND_F now dynamic).

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

WebServer.pas

@@ -298,6 +298,8 @@ type
     FXvtrBands:   TWebXvtrArray;  // список enabled XVTR (для web-UI)
     FDevices:     TWebDeviceArray; // saved+discovered устройства (для web-overlay)
     FRatePresets: array of Integer; // sample-rate пресеты текущего бэкенда (для span-кнопок)
+    FBandNames:   array of string;  // band-план текущего бэкенда (имена кнопок)
+    FBandFreqs:   array of Double;  // band-план: дефолтные частоты (для подсветки selector)
     FCurrentXvtr: Integer;        // -1 = HF, иначе индекс активного XVTR
     FOnXvtrBand:  TWebCmdXvtrBand;
 
@@ -394,6 +396,7 @@ type
     procedure SetXvtrBands(const ABands: TWebXvtrArray; ACurrent: Integer);
     procedure SetDeviceList(const ADevices: TWebDeviceArray);
     procedure SetRatePresets(const ARates: array of Integer);
+    procedure SetBands(const ANames: array of string; const AFreqs: array of Double);
     property OnSpan:   TWebCmdSpan   read FOnSpan   write FOnSpan;
     property OnVolume: TWebCmdVolume read FOnVolume write FOnVolume;
     property OnWfAGC:  TWebCmdWfAGC  read FOnWfAGC  write FOnWfAGC;
@@ -539,6 +542,10 @@ begin
   SetLength(FXvtrBands, 0);
   // Bootstrap-набор рейтов (до connect): хост перезапишет под бэкенд (HPSDR/Pluto).
   SetRatePresets([48000, 96000, 192000, 384000, 768000, 1536000]);
+  // Bootstrap band-план (HF): хост перезапишет под бэкенд на connect.
+  SetBands(['160m','80m','60m','40m','30m','20m','17m','15m','12m','10m','6m'],
+           [1840000,3700000,5357000,7100000,10120000,14200000,
+            18130000,21300000,24940000,28400000,50150000]);
 end;
 
 procedure TWebServer.SetXvtrBands(const ABands: TWebXvtrArray; ACurrent: Integer);
@@ -583,6 +590,22 @@ begin
   end;
 end;
 
+procedure TWebServer.SetBands(const ANames: array of string; const AFreqs: array of Double);
+// Band-план текущего бэкенда (из TRadioController). Web строит band-selector из
+// него — HPSDR (HF) и Pluto (VHF/UHF) имеют разные планы.
+var i: Integer;
+begin
+  FStateLock.Enter;
+  try
+    SetLength(FBandNames, Length(ANames));
+    SetLength(FBandFreqs, Length(AFreqs));
+    for i := 0 to High(ANames) do FBandNames[i] := ANames[i];
+    for i := 0 to High(AFreqs) do FBandFreqs[i] := AFreqs[i];
+  finally
+    FStateLock.Leave;
+  end;
+end;
+
 destructor TWebServer.Destroy;
 begin
   Stop;
@@ -1561,7 +1584,7 @@ const
     ('LSB','USB','DSB','CWL','CWU','FM','AM','SAM');
 var
   FS: TFormatSettings;
-  XvtrJson, DevJson, RateJson: string;
+  XvtrJson, DevJson, RateJson, BandJson: string;
   i: Integer;
 begin
   FS := DefaultFormatSettings;
@@ -1576,6 +1599,16 @@ begin
       RateJson := RateJson + IntToStr(FRatePresets[i]);
     end;
     RateJson := RateJson + ']';
+    // Сборка массива bands: [{"name":"6m","freq":50150000},...] (band-selector web).
+    BandJson := '[';
+    for i := 0 to High(FBandNames) do
+    begin
+      if i > 0 then BandJson := BandJson + ',';
+      BandJson := BandJson +
+        Format('{"name":"%s","freq":%.0f}',
+               [JsonEscape(FBandNames[i]), FBandFreqs[i]], FS);
+    end;
+    BandJson := BandJson + ']';
     // Сборка массива xvtr_bands: [{"idx":0,"name":"2m"},...]
     XvtrJson := '[';
     for i := 0 to High(FXvtrBands) do
@@ -1613,7 +1646,7 @@ begin
 	      '"status_text":"%s","board_text":"%s","ip_text":"%s","supply_text":"%s",' +
 	      '"pll_text":"%s","rx_text":"%s","tx_text":"%s","seq_text":"%s",' +
 	      '"xvtr_current":%d,"xvtr_bands":%s,"freq_mhz_digits":%d,' +
-	      '"fmstep_idx":%d,"devices":%s,"rate_presets":%s}',
+	      '"fmstep_idx":%d,"devices":%s,"rate_presets":%s,"bands":%s}',
       [FFreq, FVfoB, FActiveVfo,
        FMode, MODE_N[FMode mod 8],
        FFilterIdx, FFilterBW,
@@ -1642,7 +1675,7 @@ begin
 	       JsonEscape(FSupplyText), JsonEscape(FPLLText), JsonEscape(FRXText),
 	       JsonEscape(FTXText), JsonEscape(FSeqText),
 	       FCurrentXvtr, XvtrJson, FFreqMhzDigits,
-       FFMStepIdx, DevJson, RateJson
+       FFMStepIdx, DevJson, RateJson, BandJson
       ], FS);
   finally
     FStateLock.Leave;