Menu screens: rock background, centred frame, logo, 3D hero

- Spielen hero panel shows the selected hero in 3D (cUI_NetGranny,
  game/ui/granny.h).
- All menu screens draw on the options' rock wall; the main menu's 1024
  frame is drawn centred over it, mouse and cursor shifted to match.
- The main menu's and options' own pictures and the main menu's 3D scene
  are left out (textures hidden by surface, scene call redirected).
- Logo top left: FX_SACREDLOGO.TGA, drawn added.
- Game textures by name (game/ui/texture.h), textured and added quads.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/mods/borderless.cpp

@@ -138,6 +138,7 @@ POINT ToGame(POINT p) {
     POINT result;
     result.x = std::clamp(MulDiv(p.x - layout.client.left, layout.gameWidth, width), 0, layout.gameWidth - 1);
     result.y = std::clamp(MulDiv(p.y - layout.client.top, layout.gameHeight, height), 0, layout.gameHeight - 1);
+    result.x -= mods::hud::MenuFrameOffsetX();  // the main menu's centred frame
     return result;
 }