pyproject: restrict package discovery to pysim_otaman_server

Fix setuptools flat-layout error ('Multiple top-level packages discovered'
for frontend/ node_modules/ pysim_otaman_server/) by explicit find.include.

pyproject.toml

@@ -12,4 +12,7 @@ requires-python = ">=3.8"
 # bridge -> Twisted -> twisted-iocpsupport, which needs MSVC on Windows).
 
 [project.scripts]
-pysim-otaman-server = "pysim_otaman_server.__main__:main"
+pysim-otaman-server = "pysim_otaman_server.__main__:main"
+
+[tool.setuptools.packages.find]
+include = ["pysim_otaman_server*"]