[low] No automated tests cover scheduler and provider integration logic

[MeyerThorsten]

Severity: low
Category: testing

The repository currently has no automated test harness for the highest-risk logic paths, including provider normalization, query generation, and scheduler behavior.

Evidence:

• package.json:12-19 defines dev, build, preview, and capture scripts, but no test script.
• A repository-wide search found no *.test.*, *.spec.*, or __tests__ directories.
• Regressions like the broken Overpass query and interval = 0 scheduler behavior are exactly the kind of logic bugs tests should catch.

Impact:

• correctness regressions can ship unnoticed
• refactors in provider code and layer scheduling have little safety net
• reviewers have to rely on manual inspection for behavior that is easy to codify

Recommended fix:

• add a test runner and CI entry point
• start with focused tests for provider normalizers, Overpass query generation, and layer scheduling semantics
• then add a few API endpoint tests around the local capture server