Phase 3 (batch 31a): shared TDeviceStore for saved+discovered devices

Introduce DeviceStore.pas (TDeviceStore) as the single source of truth for
saved devices (hpsdr_devices.ini CRUD + autostart) and the current discovery
list. The controller owns one instance (created/freed in its ctor/dtor);
desktop and (later) web frontends edit/render through it so the lists never
diverge.

Refactor TDeviceDialog to use a TDeviceStore reference instead of its own
arrays + ini code. MainForm wires FDeviceDialog.Store to the controller's
store, routes discovery results (DoAddDevice) and the preload-rate lookup
through it (TDiscoveredDevice now carries the MAC), and drops the now-unused
FDevices/TDeviceItem. Behavior-preserving for the desktop dialog.

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

RadioController.pas

@@ -50,7 +50,7 @@ uses
   Classes, SysUtils, Math,
   HPSDRProtocol, HPSDRNetwork,
   WDSPEngine, AudioOutput, AudioInput,
-  Settings, ChannelStore, FMRepeater, BoardUtils;
+  Settings, ChannelStore, FMRepeater, BoardUtils, DeviceStore;
 
 type
   // Поле, которое изменилось — для гранулярных уведомлений наружу.
@@ -128,6 +128,7 @@ type
     FAudioIn:      TAudioInput;
     FSettings:     TSettingsManager;
     FChannelStore: TChannelStore;
+    FDeviceStore:  TDeviceStore;   // общий список устройств (saved+discovered)
     FWDSPReady:    Boolean;
 
     // ---- Частоты / режим / фильтр / AGC ----
@@ -413,6 +414,7 @@ constructor TRadioController.Create;
 begin
   inherited Create;
   FSettings := TSettingsManager.Create;   // владелец настроек (GUI и демон)
+  FDeviceStore := TDeviceStore.Create;    // общий список устройств (desktop+web)
   // Дефолты (дублируют TMainForm.FormCreate; в GUI перезапишутся, в демоне нужны).
   FVfoA := 14200000; FVfoB := 7100000; FActiveVfo := 0;
   FMode := 1; FFilter := 5; FFilterBW := 2700;
@@ -459,6 +461,7 @@ end;
 destructor TRadioController.Destroy;
 begin
   FreeEngines;
+  FreeAndNil(FDeviceStore);
   FreeAndNil(FSettings);
   inherited Destroy;
 end;