feat: Pluto/AD936x SDR backend (discovery, RX, VHF band plan)

Add ADALM-Pluto / AD9361 support as a second hardware backend alongside
openHPSDR, sharing the WDSP DSP pipeline and the existing controller API
(UI stays decoupled from logic).

- RadioBackend.pas: abstract TRadioBackend + TBackendCaps + TRadioDevice
  (Kind/URI/Serial). THPSDRNetwork now derives from it (state via virtual
  getters); TRadioController.FNetwork is the base type.
- IIOBindings.pas: dynamic libiio loader (runs without libiio present).
- PlutoBackend.pas: scan/probe-by-URI, connect, LO/rate/bandwidth/gain
  control, RX streaming thread (int16->24bit BE -> OnDDCIQ), Q conjugated
  to match WDSP IQ convention. Verified on LibreSDR (AD9361) over network.
- Unified discovery: TDiscoverThread scans both backends; network Plutos
  found via direct ProbeURI (no mDNS needed). ConnectDevice dispatches by
  Dev.Kind (EnsureBackend swaps backend, preserving callbacks).
- DeviceStore/DeviceForm: persist Kind/URI/Serial; save Pluto via
  AddSavedPluto so saved/autostart devices reconnect across restarts.
- VHF/UHF band plan (BoardUtils, kind-aware): 6m..ADS-B for Pluto; fixes
  HF clamps (band detect, mouse-wheel 60 MHz cap, freq-display max).
- SampleRateOverlay: configurable presets (Pluto 576k..5760k, >520 ksps),
  auto-width to fit.

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

SampleRateOverlay.pas

@@ -22,6 +22,11 @@ type
   TSampleRateOverlay = class(TComponent)
   private
     FCurrentRate:    Integer;
+    // Набор пресетов (зависит от бэкенда): HPSDR 48k..1536k или Pluto >560k.
+    // До 10 слотов (Pluto может иметь 8: 576k..5760k).
+    FRates:          array[0..9] of Integer;
+    FNames:          array[0..9] of string;
+    FRateCount:      Integer;
     FPanelHidden:    Boolean;
     FOnSpanSelect:   TSpanSelectEvent;
     FOnHidePanel:    THidePanelEvent;
@@ -31,8 +36,8 @@ type
     FWidth:          Integer;
     FHeight:         Integer;
 
-    FHitRects:   array[0..6] of TRect;   // [0]=hide button, [1..6]=span buttons
-    FHitValues:  array[0..6] of Integer; // 0=hide, else sample rate
+    FHitRects:   array[0..10] of TRect;   // [0]=hide button, [1..]=span buttons
+    FHitValues:  array[0..10] of Integer; // 0=hide, else sample rate
     FHitCount:   Integer;
     FHotIdx:     Integer;
 
@@ -67,6 +72,9 @@ type
     function HandleMouseDown(Button: TMouseButton; X, Y: Integer): Boolean;
     function HandleMouseLeave: Boolean;
     procedure SetCurrentRate(Rate: Integer);
+    // Задаёт пресеты (Гц, до 6 шт.); имена формируются как '<kHz>k'.
+    procedure SetRatePresets(const Rates: array of Integer);
+    procedure SetRatePresetsDefault;   // HPSDR 48k..1536k
     procedure SetPanelHidden(Hidden: Boolean);
     property Left: Integer read FLeft;
     property Top: Integer read FTop;
@@ -139,14 +147,15 @@ begin
   C.Font.Name  := 'Courier New';
   C.Font.Size  := 7;
   C.Font.Style := [];
-  Result := C.TextWidth(Name) + 10;
-  if Result < 36 then Result := 36;
+  Result := C.TextWidth(Name) + 8;
+  if Result < 30 then Result := 30;
 end;
 
 constructor TSampleRateOverlay.Create(AOwner: TComponent);
 begin
   inherited Create(AOwner);
   FCurrentRate := 192000;
+  SetRatePresetsDefault;
   FPanelHidden := False;
   FHitCount := 0;
   FHotIdx := -1;
@@ -207,10 +216,10 @@ begin
   TH := C.TextHeight('A');
 
   ContentW := PAD_X + HIDE_W + BTN_GAP;
-  for I := 0 to High(SPAN_NAMES) do
+  for I := 0 to FRateCount-1 do
   begin
-    Inc(ContentW, SpanBtnWidth(SPAN_NAMES[I], C));
-    if I < High(SPAN_NAMES) then Inc(ContentW, BTN_GAP);
+    Inc(ContentW, SpanBtnWidth(FNames[I], C));
+    if I < FRateCount-1 then Inc(ContentW, BTN_GAP);
   end;
   Inc(ContentW, PAD_X);
   if ContentW > W then ContentW := W;
@@ -247,11 +256,11 @@ begin
   RegisterHit(HR, 0);
   Inc(X, HIDE_W + BTN_GAP);
 
-  for I := 0 to High(SPAN_RATES) do
+  for I := 0 to FRateCount-1 do
   begin
-    BtnW := SpanBtnWidth(SPAN_NAMES[I], C);
+    BtnW := SpanBtnWidth(FNames[I], C);
     HR := Rect(X, OriginY + PAD_Y, X + BtnW, OriginY + PAD_Y + SPAN_H);
-    IsAct := SPAN_RATES[I] = FCurrentRate;
+    IsAct := FRates[I] = FCurrentRate;
     IsHot := FHotIdx = I + 1;
 
     if IsAct then       BlendRect(Target, HR, $20, $5A, $78, 220)
@@ -262,13 +271,13 @@ begin
     C.Brush.Style := bsClear;
     C.Rectangle(HR);
 
-    TW := C.TextWidth(SPAN_NAMES[I]);
+    TW := C.TextWidth(FNames[I]);
     C.Font.Color := CLR_TEXT;
     C.Brush.Style := bsClear;
     C.TextOut(HR.Left + (BtnW - TW) div 2,
-              HR.Top + (SPAN_H - TH) div 2, SPAN_NAMES[I]);
+              HR.Top + (SPAN_H - TH) div 2, FNames[I]);
 
-    RegisterHit(HR, SPAN_RATES[I]);
+    RegisterHit(HR, FRates[I]);
     Inc(X, BtnW + BTN_GAP);
   end;
 end;
@@ -278,10 +287,10 @@ var I, CW: Integer;
 begin
   C.Font.Name := 'Courier New'; C.Font.Size := 7; C.Font.Style := [];
   CW := PAD_X + HIDE_W + BTN_GAP;
-  for I := 0 to High(SPAN_NAMES) do
+  for I := 0 to FRateCount-1 do
   begin
-    Inc(CW, SpanBtnWidth(SPAN_NAMES[I], C));
-    if I < High(SPAN_NAMES) then Inc(CW, BTN_GAP);
+    Inc(CW, SpanBtnWidth(FNames[I], C));
+    if I < FRateCount-1 then Inc(CW, BTN_GAP);
   end;
   Inc(CW, PAD_X);
   if CW > AvailW then CW := AvailW;
@@ -444,10 +453,10 @@ begin
   Target.Canvas.Font.Size := 7;
   Target.Canvas.Font.Style := [];
   ContentW := PAD_X + HIDE_W + BTN_GAP;
-  for I := 0 to High(SPAN_NAMES) do
+  for I := 0 to FRateCount-1 do
   begin
-    Inc(ContentW, SpanBtnWidth(SPAN_NAMES[I], Target.Canvas));
-    if I < High(SPAN_NAMES) then Inc(ContentW, BTN_GAP);
+    Inc(ContentW, SpanBtnWidth(FNames[I], Target.Canvas));
+    if I < FRateCount-1 then Inc(ContentW, BTN_GAP);
   end;
   Inc(ContentW, PAD_X);
   ContentW := Min(ContentW, W);
@@ -524,6 +533,26 @@ begin
   end;
 end;
 
+procedure TSampleRateOverlay.SetRatePresets(const Rates: array of Integer);
+var i, n: Integer;
+begin
+  n := Length(Rates);
+  if n > 10 then n := 10;
+  FRateCount := n;
+  for i := 0 to n - 1 do
+  begin
+    FRates[i] := Rates[i];
+    FNames[i] := IntToStr(Rates[i] div 1000) + 'k';
+  end;
+  FCacheDirty := True;
+  RequestInvalidate;
+end;
+
+procedure TSampleRateOverlay.SetRatePresetsDefault;
+begin
+  SetRatePresets(SPAN_RATES);
+end;
+
 procedure TSampleRateOverlay.SetCurrentRate(Rate: Integer);
 begin
   if FCurrentRate = Rate then Exit;