fix(opengl): use Lazarus OpenGLContext

Replace OpenGLContextEx with OpenGLContext in MainForm, SpectrumViewOpengl, WaterfallViewOpengl, and WidebandView.

Switch the Lazarus project/program dependencies from LazOpenGLContextEx to LazOpenGLContext in ewsdr.lpi and ewsdr.lpr.

PixelScale was introduced in 092a202; restore the previous viewport/texture path: glViewport(0, 0, W, H), EnsureTexture(W, H), and UploadCurrentRow(W).

WidebandView.pas

@@ -18,7 +18,7 @@ interface
 
 uses
   Classes, SysUtils, Math, Graphics, Controls, ExtCtrls,
-  OpenGLContextEx, GL, AppTheme, WDSP;
+  OpenGLContext, GL, AppTheme, WDSP;
 
 type
   TWidebandView = class
@@ -1077,8 +1077,7 @@ begin
     UploadLabelTextureToGL;
     FGLBackgroundDirty := False;
   end;
-  // HiDPI: viewport в физических пикселях FBO, координаты — логические
-  glViewport(0, 0, Round(W * C.PixelScale), Round(H * C.PixelScale));
+  glViewport(0, 0, W, H);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity;
   glOrtho(0, W, 0, H, -1, 1);