feat: add PostPass query builder module to osm2pgsql-query-builder

[KenKambi]

What type of PR is this?

Check all applicable

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Related Issue :

• Contribution to Separate sql query builder & yaml parser package #304

What does this PR do ?

• Adds PostPass support to the osm2pgsql-query-builder package.
• PostPass (https://postpass.geofabrik.de/) uses the same tags ->> 'key'
  column format as osm2pgsql, so all existing filter helpers are reused from
  builder.py — no duplication.
• New: osm2pgsql_query_builder/postpass_module.py
• Updated: __init__.py
• New: tests/test_postpass.py.

A brief description of how this solves the issue.

• This PR implements the postpass_module within the new osm2pgsql-query-builder structure. It introduces specialized SQL generation logic for PostPass backends, including:
  -PostPassQueryParams & BboxFilter: Pydantic models for strict input validation.
  -build_postpass_query: Generates optimized SQL using the && (bounding box) operator for faster spatial index scans.
  -wrap_postpass_geojson: Wraps query results into a valid GeoJSON FeatureCollection directly via PostgreSQL's json_build_object

Consideration :

• A separate postpass_module.py was chosen because the PostPass backend has a meaningfully different execution model (HTTP POST vs. direct DB connection) and different table names. Keeping it isolated makes both easier to maintain and understand independently.

How to test ?

To test these changes locally, install the package in editable mode and run the suite:

# Install the package in editable mode
pip install -e osm2pgsql-query-builder

# Run the full test suite (disabling pytest_qgis if necessary)
python -m pytest osm2pgsql-query-builder/tests/ -v -p no:pytest_qgis

[KenKambi]

Hey @spwoodcock ! PR is up — 42/42 tests passing. Let me know if you'd like any changes before merging. 🙌

[spwoodcock]

Awesome, thanks Ken!

Love the tests too 🙌

I think we should merge, then I will probably rename the package - I thought I would separate everything into small packages, but that is hassle - perhaps all of this can live together in raw-data-api-py, renamed to osm-data-client