module name assumed is __main__ for .pyw files on windows

Bug Report

On windows, .pyw is a valid extension for Python files (to be executed by pythonw.exe).
mypy however assumes files with .pyw extension to have module name __main__.
This results in a False negative when 2 or more .pyw files are checked by mypy.

To Reproduce

Have mypy check 2 or more files with .pyw extension on windows.

Expected Behavior

No mypy issue.

Actual Behavior

application_2.pyw: error: Duplicate module named "__main__" (also at "application_1.pyw")
application_2.pyw: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#mapping-file-paths-to-modules for more info
application_2.pyw: note: Common resolutions include: a) using `--exclude` to avoid checking one of them, b) adding `__init__.py` somewhere, c) using `--explicit-package-bases` or adjusting MYPYPATH
Found 1 error in 1 file (errors prevented further checking)

Your Environment

Python 3.12.5
mypy==1.11.1
mypy-extensions==1.0.0
typing_extensions==4.12.2

Please run the attached windows batch file to reproduce.

test.txt

Inizia usando il file batch Windows test.txt allegato per riprodurre l'errore di modulo duplicato con due file .pyw. Poi traccia la gestione di mypy della conversione dei percorsi dei file in nomi di modulo e aggiungi un test di regressione che copra più input .pyw Windows; il lavoro è completato quando non entrano più in conflitto come main.