fix(hotkeys): find the native dialog by enumerating the thread windows

GetLastActivePopup returns the form itself - the common Save dialog is not an owned popup - so the code that raises it never ran. It does live on our thread with the standard #32770 class, which EnumThreadWindows finds regardless of its owner.

Logging confirmed two things worth keeping: WM_HOTKEY is dispatched during the dialog modal loop, and IsWindowEnabled detects the state correctly.

delphi-backend/UMainForm.pas

@@ -201,6 +201,11 @@ implementation
 
 {$R *.fmx}
 
+// Result slot for EnumOwnDialogProc — the enumeration is main-thread only and
+// consumed immediately, so a unit variable is enough.
+var
+  GFoundDialogHwnd: HWND = 0;
+
 // Forward — used by WebBrowserInitialized (which sits above the actual
 // definition lower in the unit).
 function MaskAccessToken(const AUrl: string): string; forward;
@@ -503,6 +508,24 @@ end;
 // the user can no longer find. Every hotkey entry point checks this first — and
 // rather than just refusing, it surfaces the dialog, which is what the user
 // actually needs.
+// The common Save/Open dialog is NOT an owned popup of the form —
+// GetLastActivePopup returns the form itself — but it does live on our thread
+// and carries the standard dialog class. Enumerating the thread's windows finds
+// it whoever its owner turns out to be.
+function EnumOwnDialogProc(AWnd: HWND; AParam: LPARAM): BOOL; stdcall;
+var
+  LCls: array[0..63] of Char;
+begin
+  Result := True;   // keep enumerating
+  if (AWnd = HWND(AParam)) or (not IsWindowVisible(AWnd)) then Exit;
+  if GetClassName(AWnd, LCls, Length(LCls)) = 0 then Exit;
+  if SameText(LCls, '#32770') then
+  begin
+    GFoundDialogHwnd := AWnd;
+    Result := False;   // stop
+  end;
+end;
+
 function TMainForm.NativeModalActive: Boolean;
 var
   LHwnd, LPopup: HWND;
@@ -510,7 +533,10 @@ begin
   LHwnd := WindowHandleToPlatform(Self.Handle).Wnd;
   Result := (LHwnd <> 0) and (not IsWindowEnabled(LHwnd));
   if not Result then Exit;
-  LPopup := GetLastActivePopup(LHwnd);
+  GFoundDialogHwnd := 0;
+  EnumThreadWindows(GetCurrentThreadId, @EnumOwnDialogProc, LPARAM(LHwnd));
+  LPopup := GFoundDialogHwnd;
+  if LPopup = 0 then LPopup := GetLastActivePopup(LHwnd);   // fallback
   if (LPopup <> 0) and (LPopup <> LHwnd) and IsWindow(LPopup) then
   begin
     ShowWindow(LPopup, SW_SHOW);