feat: converter reads the Phone library's register statement, named stores and generators

`init phone register` becomes a default (the group chat) plus a function of library calls that runs with
the other defaults of a new game (phone_register.py). `init/python [early|hide] in some.store` wraps its
code in an in_store node and `default some.store.name` may name a store; yield works as an expression
(generator functions are marked gen); `import x as y`, `transform -150 name(...)`, `init:` with if/else,
`config.special_namespaces` lines, `at` lists and tuples, transforms made by Python functions, `choice`
weights that are expressions, `__len__`/`__bool__`, and the whitelist for os, calendar, itertools,
pygame_sdl2 and the new runtime. The converter also records the size of every picture it converts
(`imageSizes`) so `renpy.image_size` answers without loading.

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

backend/tests/test_converter.py

@@ -57,10 +57,10 @@ def test_if_chain_and_menu():
 
 
 def test_unsupported_python_is_reported_not_fatal():
-    d = parse("init python:\n    def f():\n        received = yield 1\n    x = 1\nlabel start:\n    $ y = x\n")
+    d = parse("init python:\n    def f():\n        received = yield from other()\n    x = 1\nlabel start:\n    $ y = x\n")
     assert d.init_code[0]["op"] == "set" and "f" in d.deferred  # reported once something calls it
     from app.converter.compatibility import audit_ir
-    d = parse("init python:\n    def f():\n        received = yield 1\nlabel start:\n    $ f()\n")
+    d = parse("init python:\n    def f():\n        received = yield from other()\nlabel start:\n    $ f()\n")
     audit_ir(d)
     assert d.blockers