[high] Traffic Overpass query combines highway filters as impossible AND

[MeyerThorsten]

Severity: high
Category: bug

The OSM traffic road query concatenates multiple highway filters into a single way selector, which turns the intended OR into an impossible AND.

Evidence:

• src/layers/traffic-layer.ts:479-480 builds queries like way["highway"="motorway"]["highway"="trunk"](...).
• In Overpass, those filters all apply to the same element, so a road must have every highway value at once to match.

Impact:

• the OSM road fetch returns no useful road network
• the animated local traffic layer becomes empty or severely incomplete
• persisted OSM traffic snapshots are also wrong

Recommended fix:

• use a regex filter such as way["highway"~"^(motorway|trunk|primary|secondary)$"](...)
• or emit a union of separate way clauses instead of stacking the filters on one selector