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_renpy_universal.py

@@ -265,3 +265,23 @@ def test_starred_tuple_items_and_pickle_hooks_are_accepted():
     pgvn.statements(code)
     assert code[0]["v"]["v"][1] == {"k": "star", "v": {"k": "name", "id": "rest"}}
     assert [m["name"] for m in code[1]["body"]] == ["run"]
+
+
+def test_init_phone_register_becomes_a_default_and_a_function_of_library_calls():
+    data = parse('init phone register:\n    define "[suz]":\n        add "mc" add "suzie"\n        icon phone.asset("suzie.png")\n'
+                 '        as suzieTexts key "suzieTexts"\n    label "Earlier"\n    time year 2023 month 12 day 25 hour 7 minute 7\n'
+                 '    "suzie" "Merry Christmas!"\n    if flag:\n        "mc" "hi"\n    else:\n        "mc" "no"\n'
+                 'label start:\n    return\n')
+    assert data.defaults[0][0] == "suzieTexts" and data.defaults[0][1]["f"]["a"] == "GroupChat"
+    assert data.defaults[1][0] == "__phone_register_1_done"
+    function = next(s for s in data.init_code if s.get("op") == "def")
+    assert function["name"] == "__phone_register_1"
+    assert not data.blockers
+
+
+def test_named_stores_wrap_their_code_and_defaults_may_name_a_store():
+    data = parse('init python in phone.group_chat:\n    class GroupChat(object):\n        pass\n    def make():\n        return GroupChat()\n'
+                 'default -100 phone.menu = False\nlabel start:\n    $ x = phone.group_chat.make()\n    return\n')
+    assert data.init_code[0]["op"] == "in_store" and data.init_code[0]["ns"] == "phone.group_chat"
+    assert [s["name"] for s in data.init_code[0]["body"]] == ["GroupChat", "make"]
+    assert data.defaults[0][0] == "phone.menu"