Add freestiler recipe

[walkerke]

Checklist

• Title of this PR is meaningful: e.g. "Adding my_nifty_package".
• License file is packaged.
• Source is from official source (PyPI sdist).
• Package does not vendor other packages.
• If static libraries are linked in, the licenses of the statically linked libraries are packaged.
• Build number is 0.
• A tarball (url) rather than a repo (e.g. git_url) is used.
• GitHub users listed in the maintainer section have posted a comment confirming they are willing to be listed there.

Summary

Adds a recipe for freestiler, a Rust-powered MLT/MVT vector tile engine exposed to Python via pyo3 + maturin. It converts GeoDataFrames, GeoParquet, and DuckDB sources into PMTiles archives encoding MVT or MLT tiles.

• PyPI: https://pypi.org/project/freestiler/
• Source: https://github.com/walkerke/freestiler
• License: MIT

Not noarch — it is a compiled Rust extension, so conda-forge will produce per-platform builds. Default Cargo features (geoparquet, duckdb) build DuckDB from vendored C++ sources; happy to drop the duckdb feature in a follow-up if macOS/Windows runners time out.

Local `conda-smithy recipe-lint --conda-forge recipes/freestiler` reports "in fine form".

[walkerke]

I'm @walkerke and I'm willing to maintain this recipe.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipes/freestiler/meta.yaml) and found it was in an excellent condition.