refactor: split gpschecks.py into a subpackage (#197)

[iabaako]

Pull Request Summary 🚀

What does this PR do? 📝

Splits src/datasure/checks/gpschecks.py (2,238 lines) into a subpackage, src/datasure/checks/gpschecks/:

• models.py — module constants (TAB_NAME, MAPBOX_STYLE, _CATEGORY_COLORS); no local Pydantic models were needed since GPSSettings/GPSColumnConfig/related enums already live in datasure.models
• compute.py — pure GPS-parsing/outlier-detection functions (no Streamlit calls)
• settings_ui.py — gpschecks_report_settings and its config-UI helpers
• report_ui.py — gpschecks_report and its report-rendering UI, including the GPS column-configuration CRUD group (which, like the equivalent group in the backchecks split, turned out to be called only from the report entry point, not settings) and the Plotly/pydeck chart-rendering functions (kept here rather than compute.py since they call st.pydeck_chart/st.secrets directly, not just build-and-return a chart object)
• __init__.py — left empty, matching every other package in this repo

Also eliminates three intra-file duplicates found while splitting:

• _get_gps_column_settings/_save_gps_column_settings replace an identical duckdb_get_table/duckdb_save_table pair repeated across 6 call sites
• _identity_optional_fields dedupes 5 call sites that built (col, col) tooltip/display field pairs
• _filter_available_columns/_render_table_with_csv_download replace a repeated "filter to available columns → display → CSV download" block

Tests are mirrored into tests/checks/gpschecks/{conftest,test_models,test_compute,test_settings_ui,test_report_ui}.py, replacing the 2,757-line tests/checks/test_gpschecks.py.

This is the third of four planned splits tracked by #197 (enumerator in #265, backchecks in #266, outliers still pending), stacked on top of refactor/197-split-backchecks-module since that PR is still open.

Why is this change needed? 🤔

Per #197: gpschecks.py mixed GPS parsing/outlier-detection computation with two distinct Streamlit UI flows (settings vs. report) in one 2,238-line file.

How was this implemented? 🛠️

Pure mechanical reorganization — no logic changes, aside from the three documented deduplications above (verified to produce identical output via the existing test suite). Grepped the full src/ tree to confirm only output_view_template.py imports from this module externally, and updated it to import gpschecks_report directly from datasure.checks.gpschecks.report_ui. The generated, gitignored output_view_1.py was left untouched, per this repo's convention of never editing generated output views directly.

How to test or reproduce ? 🧪

1. uv run python -m pytest tests/checks/gpschecks --cov=datasure.checks.gpschecks --cov-report=term-missing -q — 113/113 tests pass (exact match to the pre-split count), coverage improved from 95.18% to 95.36%
2. uv run python -m pytest -q -m "not slow" — full suite passes, same pre-existing skips
3. Confirm the GPS Checks report page in the app still renders (map, outlier detection, comparison checks), and its settings still save/load correctly

Screenshots (if applicable) 📷

N/A — no UI or behavior changes.

Checklist ✅

• I have run and tested my changes locally
• I have limit this PR to less than 1000 lines of code change (if not, explain why) — ~3,600 lines changed, but this is a pure file-move/reorganization plus three small, verified dedup extractions; splitting it into multiple PRs would fragment a single mechanical refactor for no review benefit
• I have updated/added tests to cover my changes (if applicable)
• I have updated/added requirements to cover my changes (if applicable)
• I have run linting and formatting on any code changes (if applicable)
• I have updated the documentation (README, etc.) accordingly
• I have reviewed and resolved any merge conflict

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
95.2% Coverage on New Code
1.0% Duplication on New Code

See analysis details on SonarQube Cloud