The --universal flag produces a py2.py3 wheel, which is wrong for a
Python 3-only package. Switch to the modern 'build' frontend which
respects pyproject.toml and produces the correct wheel tags.

Signals to type checkers (mypy, pyright) that pygeofilter ships
inline type annotations. Without this marker, downstream consumers
cannot use the package's type hints.

The pre-commit step was commented out, meaning black, isort, flake8,
and mypy were configured but never enforced. Uncomment it so linting
is actually validated on every push and PR. Also fixes the pip3 install
invocation (was using 'python -m pip3' which doesn't work).

The docs version was hardcoded to '0.0.3' and never updated. Import
__version__ from pygeofilter.version so it stays in sync with the
package automatically.

Replace the legacy setup.py + setup.cfg + MANIFEST.in + three
requirements*.txt files with a single pyproject.toml using PEP 621
project metadata.

Changes:
- All project metadata, dependencies, and extras now in pyproject.toml
- Dev/test/docs dependencies declared as optional-dependency groups
- CI workflow uses 'pip install .[test,dev,...]' instead of requirements files
- ReadTheDocs config uses 'pip install .[docs]' with pinned Python 3.12
- Package data (*.lark, py.typed) declared via [tool.setuptools.package-data]
- Tool configs (isort, flake8, mypy, pytest) moved to pyproject.toml
- Dropped Python 3.8 from classifiers (not tested in CI)

Removed:
- setup.py, setup.cfg, MANIFEST.in
- requirements-test.txt, requirements-dev.txt, docs/requirements.txt

Ruff is a single tool that replaces all three linters/formatters,
runs ~100x faster, and is configured in one place in pyproject.toml.

Updates both the pre-commit config and the dev dependencies.

Adds pytest-cov to test dependencies and configures pytest to
automatically report coverage with missing lines on every run.

W503 is a flake8-specific rule (line break before binary operator)
that doesn't exist in Ruff. Ruff follows Black's formatting which
already handles this correctly.

Fix 6 type errors that were hidden by the mypy<=1.10.0 pin:

- ast.Like.pattern: narrow type from ScalarAstType to str (it's always
  a string — patterns can't be numeric)
- solr/evaluate.py: convert Version to str before re-wrapping
- cli.py: use dict[str, Any] for PARSERS to satisfy variance checks

Remove the mypy version pin (was <=1.10.0, now unpinned) and update
the pre-commit mirror from v1.15.0 to v2.1.0. All 56 source files
now pass mypy cleanly.

Remove 3.9 from CI matrix, classifiers, requires-python, and ruff
target-version. Minimum supported version is now Python 3.10.