chore: modernize PyPI package for Python 3.14

[ani6439walc]

Summary

• Consolidate package metadata and builds in pyproject.toml, require Python 3.14, and update all direct dependencies to their current releases.
• Move the runtime CSV into package data, preserve CSV_FILE_PATH compatibility, move the Streamlit demo to examples/, and add installed-artifact smoke coverage.
• Document the bundled CLARIN.SI dataset under CC BY-SA 4.0 while retaining MIT for source code.
• Replace legacy packaging and token-based release automation with SHA-pinned CI, verified wheel/sdist artifacts, and PyPI Trusted Publishing through OIDC.

Compatibility

• This release requires Python 3.14 or newer; Python 3.10–3.13 are intentionally no longer supported.
• Package version remains 0.0.6, and the release workflow requires the GitHub release tag to match it exactly.

Verification

• uv lock --check
• Pylint 10.00/10
• 9 pytest tests pass with 97% coverage on Python 3.14.6
• wheel and sdist pass strict metadata checks and clean-install smoke tests
• Streamlit AppTest passes with current demo dependencies
• actionlint, zizmor, and validate-pyproject pass
• runtime and all-extras/all-groups dependency audits report no known vulnerabilities

Release prerequisites

Before publishing, configure the protected GitHub Environment pypi and the matching PyPI Trusted Publisher. This PR does not create a tag, GitHub Release, or PyPI upload.