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/tests/fixtures/dunders.py

@@ -49,3 +49,15 @@ result_iter = iter([7, 8])
 result_first = next(result_iter)
 result_second = next(result_iter)
 result_default = next(result_iter, "done")
+
+
+def coro():
+    got = yield 1
+    other = yield got + 1
+    yield other * 2
+
+
+g = coro()
+result_a = next(g)
+result_b = g.send(10)
+result_c = g.send(5)