Phase 3 (batch 15): move band save/restore into the controller

Per the architecture decision, band state lifecycle belongs on the
controller (it operates entirely on controller state + engines;
persistence is already delegated to Settings.pas). A separate unit would
need friend access to ~20 fields + engines — worse coupling.

- MakeBandSettings, SaveCurrentBand: moved verbatim (pure over controller
  state; SaveCurrentBand handles the XVTR-slot vs HF band-cache split and
  delegates the write to FSettings). MainForm.SaveCurrentBand is now a thin
  delegate (22 call sites unchanged); MakeBandSettings removed from MainForm.
- RestoreBand: state + DSP application moved to the controller; rendering is
  driven by per-field Changed events (rfBand/rfMode/rfFilter/rfAGC*/rfFM*/
  rfCTun/rfVfoB). The FM filter-index sanitize (which UpdateFilterButtons
  did inline as a render side-effect) is extracted into a pure
  SanitizeFilterForMode so the DSP ApplyModeFilter still runs on the
  sanitized BW (preserves original ordering). Fixes the same AGC index-cast
  bug as earlier batches (now ApplyAGCToEngine).
- MainForm.RestoreBand is a thin wrapper: ResetWfAvgBuf (band-switch-only,
  not per-tune) + controller.RestoreBand + ApplyVfoA(FVfoA) for the final
  tune with channel orchestration (auto-CTCSS / pre-channel drive).
- Added rfFMStep render case (BtnFMStep on/off was styled ad-hoc).

Builds clean, links.

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

MainForm.pas

@@ -412,7 +412,6 @@ type
     procedure RestoreWindowBounds;
     procedure SaveWindowBounds;
     function  MakeGlobalSettings: TGlobalSettings;
-    function  MakeBandSettings: TBandSettings;
     procedure FreqDispBChanged(Sender: TObject; NewFreq: Int64);
     procedure BtnBandClick(Sender: TObject);
     procedure BtnModeClick(Sender: TObject);
@@ -787,28 +786,6 @@ begin
   FController.FSettings.SaveWindowBounds(L, T, Wd, Ht, DPI, Maximized);
 end;
 
-function TMainForm.MakeBandSettings: TBandSettings;
-begin
-  Result.VfoA      := FController.FVfoA;
-  Result.VfoB      := FController.FVfoB;
-  Result.Mode      := FController.FMode;
-  Result.FilterIdx := FController.FFilter;
-  Result.FilterBW  := FController.FFilterBW;
-  Result.AGCMode   := FController.FAGCMode;
-  Result.AGCTop    := FController.FAGCTop;
-  Result.CTun      := FController.FCTun;
-  Result.SpanHz    := FController.FSpanHz;
-  Result.FMSQOn       := FController.FFMSQOn;
-  Result.FMSQLevel    := FController.FFMSQLevel;
-  Result.CTCSSOn      := FController.FFMCTCSSOn;
-  Result.CTCSSToneIdx := FController.FFMCTCSSToneIdx;
-  Result.FMStepOn     := FController.FFMStepOn;
-  Result.FMStepIdx    := FController.FFMStepIdx;
-  Result.FMRptDir      := FController.FFMRptDir;
-  Result.FMRptOffsetHz := FController.FFMRptOffsetHz;
-  // Waterfall AGC/NF — глобальные (не диапазонные)
-end;
-
 function TMainForm.MakeGlobalSettings: TGlobalSettings;
 var i: Integer;
 begin
@@ -889,124 +866,21 @@ end;
 
 procedure TMainForm.SaveCurrentBand;
 begin
-  if not FController.FDevConnected then Exit;
-  // В XVTR-режиме НЕ трогаем HF band-cache: FController.FBandCache[FController.FCurrentBand]
-  // относится к HF-диапазону, на котором пользователь был ДО активации
-  // трансвертера, и FController.FVfoA сейчас на XVTR-частоте (144.x, 432.x и т.д.).
-  // Запись в FController.FBandCache[FController.FCurrentBand] стерла бы корректное HF-состояние.
-  // Вместо этого сохраняем LastFreq в XVTR-настройках.
-  if FController.FCurrentXvtr >= 0 then
-  begin
-    if (FController.FCurrentXvtr < CFG_XVTR_COUNT) then
-    begin
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFreq         := FController.FVfoA;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastMode         := FController.FMode;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFilterIdx    := FController.FFilter;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMSQOn       := FController.FFMSQOn;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMSQLevel    := FController.FFMSQLevel;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastCTCSSOn      := FController.FFMCTCSSOn;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastCTCSSToneIdx := FController.FFMCTCSSToneIdx;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMStepOn     := FController.FFMStepOn;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMStepIdx    := FController.FFMStepIdx;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMRptDir        := FController.FFMRptDir;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMRptOffsetHz   := FController.FFMRptOffsetHz;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastCTun            := FController.FCTun;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastAGCMode         := FController.FAGCMode;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastAGCTop          := FController.FAGCTop;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastCTCSSAutoActive := FController.FFMCTCSSAutoActive;
-      FController.FXvtrSettings.Entries[FController.FCurrentXvtr].LastFMRptAutoActive := FController.FFMRptAutoActive;
-    end;
-    FController.FSettings.SaveXvtr(FController.FDevMAC, FController.FXvtrSettings);
-    Exit;
-  end;
-  // Не сохраняем, если VFO ушёл в VHF/UHF область (например, после применения
-  // канала на 2м без XVTR) — иначе HF-кэш диапазона будет перезаписан VHF-частотой.
-  if FController.FVfoA > 61000000 then Exit;
-  FController.FBandCache[FController.FCurrentBand] := MakeBandSettings;
-  FController.FSettings.SaveBand(FController.FDevMAC, FController.FCurrentBand, FController.FBandCache[FController.FCurrentBand]);
+  // Логика сохранения (band-cache/XVTR-слот + конфиг) — в контроллере.
+  FController.SaveCurrentBand;
 end;
 
 procedure TMainForm.RestoreBand(BandIdx: Integer);
-var
-  B: TBandSettings;
-  i: Integer;
 begin
   if (BandIdx < 0) or (BandIdx >= CFG_BAND_COUNT) then Exit;
-  B := FController.FBandCache[BandIdx];
-
-  // --- Кнопки диапазонов ---
-  for i := 0 to BAND_COUNT - 1 do
-    StyleButton(BtnBand[i], i = BandIdx);
-  // Сбрасываем waterfall thresholds при смене диапазона
+  // Сброс порогов водопада — только при явной смене диапазона (не на каждом
+  // пересечении границы при тюнинге, поэтому здесь, а не в rfBand-рендере).
   FSpecView.ResetWfAvgBuf;
-
-  // --- Режим: сначала устанавливаем FController.FMode, потом кнопки и WDSP ---
-  FController.FMode := B.Mode;
-  for i := 0 to MODE_COUNT - 1 do
-    StyleButton(BtnMode[i], i = FController.FMode);
-  if FController.FWDSPReady then
-    FController.FDSPEngine.SetMode(FController.FMode);
-
-  // --- Фильтр ---
-  FController.FFilter   := B.FilterIdx;
-  FController.FFilterBW := B.FilterBW;
-  UpdateFilterButtons;          // обновляет кнопки фильтра
-  FController.ApplyModeFilter;              // применяет Lo/Hi в WDSP с учётом нового FController.FMode
-
-  // --- AGC ---
-  FController.FAGCMode := B.AGCMode;
-  FController.FAGCTop  := B.AGCTop;
-  for i := 0 to 4 do
-    StyleButton(BtnAGCMode[i], i = FController.FAGCMode);
-  TrkAGC.Position := FController.FAGCTop;
-  LblAGCTop.Caption := Format('%ddB', [FController.FAGCTop]);
-  if FController.FWDSPReady then
-  begin
-    FController.FDSPEngine.SetAGCTop(FController.FAGCTop);
-    FController.FDSPEngine.SetAGC(TWDSPAGCMode(FController.FAGCMode), 50.0);
-  end;
-  FSpecView.AGCTop := FController.FAGCTop;
-
-  // --- FM Squelch + CTCSS ---
-  FController.FFMSQOn    := B.FMSQOn;
-  FController.FFMSQLevel := B.FMSQLevel;
-  // UI update happens inside UpdateFilterButtons (called above) when mode=FM
-  FController.FFMCTCSSOn := B.CTCSSOn;
-  if BtnFMCTCSS <> nil then StyleButton(BtnFMCTCSS, FController.FFMCTCSSOn);
-  SetFMCTCSSTone(B.CTCSSToneIdx);
-  ApplyFMSquelch;
-  FController.FFMStepOn := B.FMStepOn;
-  SetFMStep(B.FMStepIdx);
-  if BtnFMStep <> nil then StyleButton(BtnFMStep, FController.FFMStepOn);
-  FController.FFMRptDir      := B.FMRptDir;
-  FController.FFMRptOffsetHz := B.FMRptOffsetHz;
-  if FController.FFMRptOffsetHz <= 0 then
-    FController.FFMRptOffsetHz := RptDefaultOffsetHz(B.VfoA);
-  if BtnFMRptMinus <> nil then StyleButton(BtnFMRptMinus, FController.FFMRptDir = RPT_MINUS);
-  if BtnFMRptPlus  <> nil then StyleButton(BtnFMRptPlus,  FController.FFMRptDir = RPT_PLUS);
-  if EdFMRptOffset <> nil then EdFMRptOffset.Text := RptFormatOffset(FController.FFMRptOffsetHz);
-
-  // --- CTUN ---
-  FController.FCTun := B.CTun;
-  StyleButton(BtnCTun, FController.FCTun);
-  if FController.FWDSPReady and not FController.FCTun then
-    FController.FDSPEngine.SetShift(0.0);
-
-  // --- Sample Rate / Span ---
-  // SampleRate — глобальный, не per-band. Не восстанавливаем из диапазона.
-  FController.FSpanHz := FController.FSampleRate;
-  if Assigned(FSampleRateOverlay) then
-    FSampleRateOverlay.SetCurrentRate(FController.FSampleRate);
-
-  // --- VFO A: центрируем на новой частоте, сбрасываем shift ---
-  FController.FCenterFreq := B.VfoA;        // DDC = центр диапазона
-  FController.FVfoB       := B.VfoB;
-  FreqDispB.Frequency := Round(FController.FVfoB);
-
-  // Пересчитываем drive byte для нового диапазона перед отправкой в сеть
-  FController.FDriveLevel := CalcDriveByte;
-  // ApplyVfoA обновит сеть, FreqDisp, shift, Ruler — перерисует.
-  ApplyVfoA(Round(B.VfoA));
+  // Состояние + DSP + события рендера — в контроллере.
+  FController.RestoreBand(BandIdx);
+  // Финальная перестройка VFO A с канальной оркестрацией (auto-CTCSS,
+  // pre-channel drive) — через UI-путь ApplyVfoA.
+  ApplyVfoA(Round(FController.FVfoA));
 end;
 
 procedure TMainForm.SaveAllAndExit;
@@ -1492,6 +1366,12 @@ begin
           if (FController.FMode = MODE_FM) and (FSpecView <> nil) then
             FSpecView.FMGridStepHz := FM_STEP_HZ[FController.FFMStepIdx];
         end;
+      rfFMStep:
+        if BtnFMStep <> nil then
+        begin
+          StyleButton(BtnFMStep, FController.FFMStepOn);
+          BtnFMStep.Repaint;
+        end;
       rfFMSQ:
         begin
           StyleButton(BtnFMSQ, FController.FFMSQOn);