Add python tests via Tox

[ppinchuk]

Long time coming

[Copilot]

Pull Request Overview

This PR adds Python test infrastructure using Tox for testing across multiple Python versions (3.12, 3.13, 3.14) and updates test fixtures, dependencies, and CI workflows accordingly.

Key Changes:

• Introduces Tox configuration for multi-version Python testing
• Updates test fixtures from test_data_dir to test_data_files_dir
• Consolidates Python checks (linting and testing) into a single CI workflow

Reviewed Changes

Copilot reviewed 13 out of 61 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tox.ini	Adds Tox configuration for testing across Python 3.12-3.14 with specific dependency versions
.github/workflows/ci-python.yml	New consolidated workflow for linting, unit tests, integration tests, and Tox-based tests
.github/workflows/lint-python.yml	Removed (consolidated into ci-python.yml)
tests/python/conftest.py	Adds test_data_files_dir fixture to complement existing test_data_dir
tests/python/validation/*.py	Updates test fixtures to use test_data_files_dir
tests/python/test_integrated.py	Updates error handling and search engine import
pyproject.toml	Updates pytest configuration and adds explicit dependency constraints
pixi.lock	Downgrades several dependencies to ensure compatibility
compass/data/conus_jurisdictions.csv	Adds descriptive names to Maryland district subdivisions

Comments suppressed due to low confidence (1)

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[Copilot]

Pull Request Overview

Copilot reviewed 15 out of 61 changed files in this pull request and generated 1 comment.

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[ppinchuk]

@castelao this is ready for review

[castelao]

This is great! Thanks Paul! I have just a few minor comments.

[ppinchuk]

@castelao This is ready for re-review