games: fix font glyphs, Snake edge-wrap, snappier Snake

Font: add missing bitmap glyphs (/ # * + =) to both Snake and Tetris so
control labels like '4/6 MOVE' and '# PAUSE' render correctly. Also hoist
XSetForeground out of the per-pixel loop in draw_text (both games).

Snake: remove the wall-collision death; the head now wraps through the
opposite edge ((hx+COLS)%COLS, (hy+ROWS)%ROWS). Base speed raised from
70->100 px/sec (~128ms -> ~90ms per step) so it feels less laggy; the
+1 px/sec per 5 food progressive difficulty is unchanged.

src/games/tetris.cpp

@@ -72,6 +72,11 @@ static const Glyph GLYPHS[] = {
   {'7', {0b11111,0b00001,0b00010,0b00100,0b01000,0b01000,0b01000}},
   {'8', {0b01110,0b10001,0b10001,0b01110,0b10001,0b10001,0b01110}},
   {'9', {0b01110,0b10001,0b10001,0b01111,0b00001,0b00010,0b01100}},
+  {'/', {0b00001,0b00010,0b00100,0b00100,0b01000,0b01000,0b10000}},
+  {'#', {0b01010,0b01010,0b11111,0b01010,0b11111,0b01010,0b01010}},
+  {'*', {0b00100,0b01010,0b11111,0b01010,0b00100,0b00000,0b00000}},
+  {'+', {0b00000,0b00100,0b00100,0b11111,0b00100,0b00100,0b00000}},
+  {'=', {0b00000,0b00000,0b11111,0b00000,0b11111,0b00000,0b00000}},
 };
 static const int NGLYPH = int(sizeof(GLYPHS) / sizeof(GLYPHS[0]));
 static const unsigned char* glyph(char c) {
@@ -245,15 +250,14 @@ static void reset_game() {
 
 static void draw_text(int x, int y, int scale, unsigned long col, const char* s) {
   int cx = x;
+  XSetForeground(dpy, gc, col);
   for (const char* p = s; *p; p++) {
     const unsigned char* g = glyph(*p);
     for (int r = 0; r < 7; r++) {
       unsigned char row = g[r];
       for (int b = 0; b < 5; b++)
-        if (row & (1 << (4 - b))) {
-          XSetForeground(dpy, gc, col);
+        if (row & (1 << (4 - b)))
           XFillRectangle(dpy, back, gc, cx + b * scale, y + r * scale, scale, scale);
-        }
     }
     cx += 6 * scale;
   }