Copenhagen Phase 1: scaffolding + area + OSM download

- pyproject.toml with all deps (geopandas, contextily, partridge, etc.)
- config/: area.json (3 OSM boundary relations), modes.yaml (subway/s_tog/
  light_rail/regional/bus, S-tog scoped to route=light_rail network=Takst),
  styling.yaml (zorder/widths/colours/palette/mask/labels)
- build_area.py: fetch 3 relations via OSM API, stitch rings, dissolve to
  area.gpkg/area.geojson (City Pass approximation)
- download_osm.py: per-mode Overpass (mirror+backoff, out geom + recurse for
  stops), writes {mode}.gpkg (lines+stops) + query text
- download_gtfs.py / gtfs_to_geopackage.py: stubs (blocked on Rejseplanen)
- data/ gitignored (regenerable); output/ tracked

copenhagen/config/modes.yaml

@@ -0,0 +1,40 @@
+# Mapping of map modes to OSM route filters, GTFS route types, and style keys.
+# `style` references a key in styling.yaml.
+#
+# OSM filter keys map directly to Overpass tag filters. A key suffixed with
+# `_neq` emits a negated tag filter (["k"!="v"]); any other key emits an
+# equality filter (["k"="v"]). The bbox is appended by download_osm.py.
+#
+# S-tog are tagged route=light_rail in OSM (NOT route=train); they are scoped
+# by network="Takst Sjælland". The separate `light_rail` mode catches other
+# light rail (e.g. Hovedstadens Letbane, opened Aug 2026) via network!=Takst.
+# GTFS route_type: 0=tram,1=subway,2=rail,3=bus,4=ferry.
+modes:
+  subway:
+    osm:
+      route: subway
+    gtfs_route_type: 1
+    style: metro
+  s_tog:
+    osm:
+      route: light_rail
+      network: "Takst Sjælland"
+    gtfs_route_type: 2
+    style: s_tog
+  light_rail:
+    osm:
+      route: light_rail
+      network_neq: "Takst Sjælland"
+    gtfs_route_type: 2
+    style: light_rail
+  regional:
+    osm:
+      route: train
+    gtfs_route_type: 2
+    style: regional
+  bus:
+    osm:
+      route: bus
+      network: Movia
+    gtfs_route_type: 3
+    style: bus