[Code scan] Fix package contents to exclude tests and include examples consistently

[njzjz]

This issue is a result of a Codex global code scan of deepmodeling/fpop at commit b05b337590c31a5237b2dcbd9c0833b841c08cd4.

Relevant code:

fpop/setup.py

Lines 15 to 23 in b05b337

	packages=setuptools.find_packages(),
	install_requires=[
	"pydflow",
	"lbg",
	"dpdata",
	"numpy",
	"ase",
	"dargs",
	],

fpop/MANIFEST.in

Line 1 in b05b337

include LICENSE

Problem:
The wheel and source distribution currently package different unintended content:

• packages=setuptools.find_packages() includes the repository's top-level tests package because it is a Python package under the repo root.
• MANIFEST.in includes only LICENSE, so the source distribution omits the runnable examples/** files that are present in the repository.

Validation from the current tree:

wheel has tests package True
sample tests entries ['tests/__init__.py', 'tests/constants.py', 'tests/context.py', 'tests/mocked_ops.py', 'tests/test_abacus_inputs.py']
sdist has examples False
sdist has tests True

Expected behavior:
Runtime distributions should not install a top-level tests package into user environments. If examples are intended to be shipped, MANIFEST.in should include them; otherwise documentation should not imply they are available from the source distribution.