feat: switch text to UTF-8; add Unicode key events, dead keys & Czech layout; fix numpad navigation; add NumLock support

programs/include/gui/canvas.hpp

@@ -165,9 +165,9 @@ struct Canvas {
         if (!str || !font_data || scale <= 0) return;
         uint32_t pixel = c.to_pixel();
         int cx = x;
-        for (int i = 0; str[i]; i++, cx += FONT_WIDTH * scale) {
+        for (const char* p = str; *p; cx += FONT_WIDTH * scale) {
             const uint8_t* glyph =
-                &font_data[(unsigned char)str[i] * FONT_HEIGHT];
+                &font_data[cp437_index(montauk::utf8::next(&p)) * FONT_HEIGHT];
             for (int row = 0; row < FONT_HEIGHT; row++) {
                 uint8_t bits = glyph[row];
                 if (!bits) continue;