Add four animated KonoSuba ESPHome pages

Megumin's daily explosion, the Adventurers' Guild quest board (agenda,
weather, solar), Megumin's adventurer card and a party battle against a
giant toad with a live-data battle log. Original 1-bit pixel art lives in
tools/konosuba_sprites.py, which generates konosuba_sprites.h and can
render a preview PNG.

Home data and drawing helpers shared by the themed pages move to
el512_pages.h; the display gains dither_mask() for a dissolve-in intro.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

components/el512/cyberpunk.cpp

@@ -23,42 +23,11 @@ constexpr int W = 512, H = 256;
 
 // --- Small helpers -----------------------------------------------------------
 
-// Integer hash for repeatable pseudo-random effects (lowbias32).
-uint32_t hash(uint32_t x) {
-  x ^= x >> 16;
-  x *= 0x7feb352d;
-  x ^= x >> 15;
-  x *= 0x846ca68b;
-  x ^= x >> 16;
-  return x;
-}
-uint32_t hash(uint32_t a, uint32_t b) { return hash(a * 0x9e3779b9u ^ hash(b)); }
-
-std::string str(const char *fmt, ...) __attribute__((format(printf, 1, 2)));
-std::string str(const char *fmt, ...) {
-  char buf[96];
-  va_list args;
-  va_start(args, fmt);
-  vsnprintf(buf, sizeof(buf), fmt, args);
-  va_end(args);
-  return buf;
-}
-
-std::string upper(std::string s) {
-  for (auto &c : s)
-    c = (char) toupper((unsigned char) c);
-  return s;
-}
+using namespace fx;
 
 std::string temp_text(float v, const char *unit = "°") { return std::isnan(v) ? "--" : str("%.1f%s", v, unit); }
 std::string watts_text(float v) { return std::isnan(v) ? "--" : watts(v); }
 
-int text_width(Display &it, display::BaseFont *font, const char *text) {
-  int x, y, w, h;
-  it.get_text_bounds(0, 0, text, font, TextAlign::TOP_LEFT, &x, &y, &w, &h);
-  return w;
-}
-
 const char *const CODES[] = {"1C", "55", "BD", "E9", "7A", "FF"};
 constexpr int CODE_COUNT = 6;