feat: player runtime for the Phone library and That New Teacher

Named stores (PyNamespace: dotted access, functions that see their own store first, restored after a
save is loaded), real generators run step by step (next, send, yield as an expression), len/bool through
__len__/__bool__, os/calendar/itertools/pygame_sdl2 helpers, Skip and ToggleLocalVariable actions,
text tags {glitch} and {wave} and plain display of explode/gradient/ruby, SnowBlossom and anim.Blink,
RoundedCorners as a transform, transforms listed in `at`, ATL choice weights that are flags, and
renpy.image_size from the converter's picture sizes.

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

frontend/src/player/player.css

@@ -376,6 +376,14 @@
 .pg-fx-sc { animation: pg-fx-scare 0.12s linear infinite; }
 .pg-fx-fi { animation: pg-fx-in 0.6s ease-out both; }
 .pg-fx-rotat { animation: pg-fx-spin 2s linear infinite; }
+.pg-fx-glitch { animation: pg-fx-glitch 0.35s steps(2, end) infinite; text-shadow: 1px 0 #f0f, -1px 0 #0ff; }
+.pg-fx-wave { animation: pg-fx-wave 1.2s ease-in-out infinite; }
+@keyframes pg-fx-glitch { 20% { transform: translate(-1px, 1px); } 40% { transform: translate(1px, -1px); } 60% { transform: translate(-2px, 0); } 80% { transform: translate(2px, 1px); } }
+@keyframes pg-fx-wave { 50% { transform: translateY(-4px); } }
+/* SnowBlossom: pictures that fall and drift while the scene is shown */
+.pg-snow { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }
+.pg-snow > * { position: absolute; top: -10%; animation: pg-snow-fall linear infinite; }
+@keyframes pg-snow-fall { from { transform: translate(0, 0); } to { transform: translate(var(--drift, 40px), 120vh); } }
 @keyframes pg-fx-bounce { 50% { transform: translateY(calc(var(--fx, 6) * -1px)); } }
 @keyframes pg-fx-scare { 25% { transform: translate(1px, -1px); } 75% { transform: translate(-1px, 1px); } }
 @keyframes pg-fx-in { from { opacity: 0; transform: translateY(8px); } }