fix(osm): stop using public Overpass by default (#648) (#742)

Traffic roads come from OpenFreeMap vector tiles, or TomTom flow tiles with a
key (Hybrid by default). Military areas use OpenFreeMap polygons with a bundled
worldwide name index; wide views show named points. ALPR reads an hourly
OpenStreetMap extract. Cockpit place context and country, state and US county
outlines use bundled Natural Earth and US Census data. Overpass is used only
when an operator configures their own endpoint.

Also: camera arrivals no longer land below ground, keyless terrain retries on
429, bounded relation geometry for configured Overpass, one shared
OpenStreetMap credit, and separate tile and API transports for embedders.

Co-authored-by: theGaryLarson <[email protected]>
Co-authored-by: Milan Khanal <[email protected]>

.env.example

@@ -183,3 +183,6 @@ AISSTREAM_API_KEY=
 # CCTV_MAX_SOURCES=4000                                # catalog-wide ceiling, shared round-robin across packs
 # CCTV_PREFER_AUSTIN=1                                 # prioritize Austin cameras in the registry
 # CCTV_FORCE_AUSTIN=                                   # force live default sources when a source-pack JSON is configured
+
+# Optional: comma-separated Overpass URLs; use only instances you run or pay for.
+OVERPASS_UPSTREAMS=