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/app/converter/screens.py

@@ -178,7 +178,7 @@ class ScreenParser:
         while i < len(lines):
             line = lines[i]
             text = line.text.rstrip(":").strip() if line.block else line.text.strip()
-            text = re.sub(r"^(add|text|label|image|textbutton)(?=[\"'])", r"\1 ", text)  # `add"cover"`
+            text = re.sub(r"^(add|text|label|image|textbutton)(?=[\"'(])", r"\1 ", text)  # `add"cover"`, `textbutton(_("x"))`
             words = tokens(re.sub(r"^(if|elif|showif)\(", r"\1 (", text))
             i += 1
             if not words:
@@ -412,6 +412,18 @@ class ScreenParser:
             spec["atl"] = animation
         props["at"] = [*props.get("at", []), spec]
 
+    def at_refs(self, source: str, line: Line) -> list[Node]:
+        """The entries of one `at` item: `(a, b)` is two of them."""
+        text = source.strip()
+        if text[:1] in "([" and text[-1:] in ")]":
+            try:
+                tree = ast.parse(text, mode="eval").body
+            except SyntaxError:
+                tree = None
+            if isinstance(tree, (ast.Tuple, ast.List)):
+                return [spec for element in tree.elts for spec in self.at_refs(ast.unparse(element), line)]
+        return [self.at_ref(source, line)]
+
     def at_ref(self, source: str, line: Line) -> Node:
         """One `at` entry; `(a if cond else b)` picks a transform while the screen is shown."""
         text = source.strip()
@@ -427,7 +439,7 @@ class ScreenParser:
                                        "else": self.at_ref(ast.unparse(tree.orelse), line)}}
         if text == "None":
             return {}
-        if re.fullmatch(r"[A-Za-z_]\w*(?:\.\w+)*\[[^\]]+\]|[A-Za-z_]\w*\.\w+", text):  # `icon["at"]`, `item.at`
+        if re.fullmatch(r"[A-Za-z_]\w*(?:\.\w+)*\[[^\]]+\]|[A-Za-z_]\w*(?:\.\w+)+", text):  # `icon["at"]`, `item.at`
             dynamic = self.expr(text, line)
             if dynamic is not None:
                 return {"dyn": dynamic}
@@ -466,7 +478,7 @@ class ScreenParser:
                     i += 1
                     if not more:
                         break
-                props["at"] = [self.at_ref(item, line) for item in items if item]
+                props["at"] = [spec for item in items if item for spec in self.at_refs(item, line)]
                 continue
             if glued is not None:
                 source, i = glued, i + 1