feat: mousearea, datetime dates, dir(), renpy.image_size and style.rebuild for Ren'Py games

Screens get an invisible mousearea that reports the pointer entering and leaving without taking
clicks. datetime.date/datetime/timedelta support construction and date arithmetic. dir() lists the
game's variables, renpy.style.rebuild() is a no-op, and renpy.image_size answers only for pictures
the browser already holds (otherwise an IOError the game can catch).

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

backend/app/converter/compatibility.py

@@ -120,6 +120,8 @@ CALLS |= {"renpy.start_predict", "renpy.stop_predict", "renpy.start_predict_scre
           "renpy.ui.imagebutton", "renpy.return_statement"}
 from app.games.renpy_native import NATIVE_CLASSES, NATIVE_METHODS  # noqa: E402
 CALLS |= set(NATIVE_CLASSES)
+CALLS |= {"dir", "datetime.date", "datetime.datetime", "datetime.timedelta", "date", "timedelta",
+          "renpy.style.rebuild", "renpy.image_size"}
 CALLS |= {"map", "filter", "iter", "hash", "hasattr", "getattr", "setattr", "callable", "super"}
 # Screen actions and values the player implements (see frontend/src/player/screens.ts)
 SCREEN_CALLS = set("""Jump Call Return SetVariable ToggleVariable SetDict SetField ToggleField

backend/app/converter/screens.py

@@ -31,7 +31,7 @@ Node = dict[str, Any]
 OPENERS = {"Show", "ShowTransient", "ToggleScreen", "Hide", "show_screen", "call_screen", "hide_screen"}
 
 CONTAINERS = {"fixed", "frame", "window", "vbox", "hbox", "grid", "vpgrid", "viewport", "button", "side", "nearrect"}
-LEAVES = {"text", "label", "textbutton", "imagebutton", "add", "image", "null", "bar", "vbar"}
+LEAVES = {"text", "label", "textbutton", "imagebutton", "add", "image", "null", "bar", "vbar", "mousearea"}
 POSITIONAL = {"side": 1, "text": 1, "label": 1, "textbutton": 1, "add": 1, "image": 1, "grid": 2}
 ATL_WORDS = {"pause", "repeat", "parallel", "choice", "block", "contains", "function", "time"}