fix: cap Python metadata before 3.15

[qybaihe]

Summary

Fixes #2006.

Cap the published Python requirement at >=3.10,<3.15 so resolvers do not try to solve Crawl4AI for currently unsupported future Python 3.15+ environments. The existing PyPI metadata for 0.8.7-0.8.9 is already >=3.10; this change narrows the declared range to the Python versions the package can reasonably resolve against today while preserving the current lower bound.

List of files changed and why

• pyproject.toml - update the primary package metadata requires-python range.
• setup.py - keep the legacy setuptools entry point in sync with pyproject.toml.
• tests/test_python_requires_metadata.py - add a focused regression test that checks both metadata entry points stay aligned.

How Has This Been Tested?

• uv run --no-project --with pytest pytest tests/test_python_requires_metadata.py
• uv build --wheel --out-dir "$tmpdir" and inspected the generated wheel METADATA, confirming Requires-Python: >=3.10,<3.15.

Note: I did not update uv.lock with my local uv 0.7.6 because it would downgrade the lockfile format and re-resolve unrelated dependencies. The package metadata generated from the build is correct without a lockfile rewrite.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas (not applicable; no complex code added)
• I have made corresponding changes to the documentation (not applicable; package metadata only)
• I have added/updated unit tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes