fix(games): inset windows so dwm's native border stays on-screen

dwm adds a borderpx (1) border around every client, so a window sized to
fill the usable area (240x296) overflowed the 240x320 screen by 2px on the
right and bottom, clipping the native window border. Offset the requested
position by the border width and shrink by 3*borderpx so the framed window
exactly meets the screen edges with the native border fully visible.

src/games/snake.cpp

@@ -287,11 +287,16 @@ static void setup_window() {
   screen = DefaultScreen(dpy);
   int sw = DisplayWidth(dpy, screen);
   int scrH = DisplayHeight(dpy, screen);
-  winW = sw;
+  // dwm draws a `borderpx` border around every client (src/sxmo-dwm/config.h).
-  winH = scrH - TOPBAR;          // fill the area below the status bar
+  // Size/position the window so that, once dwm adds its border back on each
+  // side, the framed window exactly meets the screen edges and the native
+  // border stays fully visible instead of being clipped off the right/bottom.
+  int bw = 1;                       // must match dwm borderpx
+  winW = sw - 3 * bw;
+  winH = (scrH - TOPBAR) - 3 * bw;  // room for the status bar + border
   if (winW < 96) winW = 96;
   if (winH < 96) winH = 96;
-  win = XCreateWindow(dpy, RootWindow(dpy, screen), 0, 0, winW, winH, 0,
+  win = XCreateWindow(dpy, RootWindow(dpy, screen), bw, TOPBAR + bw, winW, winH, 0,
                        CopyFromParent, InputOutput, CopyFromParent, 0, nullptr);
   XStoreName(dpy, win, "Snake");
   XClassHint* ch = XAllocClassHint();

src/games/tetris.cpp

@@ -329,11 +329,16 @@ static void setup_window() {
   screen = DefaultScreen(dpy);
   int sw = DisplayWidth(dpy, screen);
   int scrH = DisplayHeight(dpy, screen);
-  winW = sw;
+  // dwm draws a `borderpx` border around every client (src/sxmo-dwm/config.h).
-  winH = scrH - TOPBAR;          // fill the area below the status bar
+  // Size/position the window so that, once dwm adds its border back on each
+  // side, the framed window exactly meets the screen edges and the native
+  // border stays fully visible instead of being clipped off the right/bottom.
+  int bw = 1;                       // must match dwm borderpx
+  winW = sw - 3 * bw;
+  winH = (scrH - TOPBAR) - 3 * bw;  // room for the status bar + border
   if (winW < 96) winW = 96;
   if (winH < 96) winH = 96;
-  win = XCreateWindow(dpy, RootWindow(dpy, screen), 0, 0, winW, winH, 0,
+  win = XCreateWindow(dpy, RootWindow(dpy, screen), bw, TOPBAR + bw, winW, winH, 0,
                        CopyFromParent, InputOutput, CopyFromParent, 0, nullptr);
   XStoreName(dpy, win, "Tetris");
   XClassHint* ch = XAllocClassHint();