feat: last touches to maps feature (#1389)

Author: cka-y

web-app/public/locales/en/feeds.json

@@ -188,12 +188,13 @@
     "bodyLarge": "We’re indexing stops across the full extent. This might take a moment.",
     "body": "We’re indexing stops across the view to speed up filtering.",
     "gridTile": "Grid: {{grid}} • Tile {{tile}} / {{total}}",
-    "percentComplete": "{{percent}}% complete"
+    "percentComplete": "{{percent}}% complete",
+    "cancel": "Cancel"
   },
   "fullMapView": {
     "disabledTitle": "Full map view disabled",
     "disabledDescription": "The full map view feature is disabled at the moment. Please try again later.",
-    "dataBlurb":"Tiles are built from the GTFS feed: we read routes.txt, trips.txt, stop_times.txt, stops.txt (and shapes.txt when present), derive routes/stops to GeoJSON, compile them with Tippecanoe into pmtiles files for map rendering.",
+    "dataBlurb":"The visualization reflects data directly from the GTFS feed. Route paths, stops, colors, and labels are all derived from the feed files (routes.txt, trips.txt, stop_times.txt, stops.txt, and shapes.txt where it's defined). If a route doesn’t specify a color, it appears in black. When multiple shapes exist for different trips on the same route, they’re combined into one for display.",
     "clearAll": "Clear All",
     "hideStops": "Hide Stops",
     "closePanel": "Close",