cleanup: drop coord backfill, drop transit overlay, block PM autofill

- Remove the admin "Koordinaten nachladen" button, /actions/backfill-coords
  endpoint, geocode.py, googlemaps dep, GMAPS_API_KEY plumbing in the web
  service, and the map diagnostic line. Going-forward geocoding happens in
  alert on scrape; upsert_flat backfill on re-submit remains for edge cases
- Remove the OpenRailwayMap transit overlay (visually noisy); keep CartoDB
  Voyager as the sole basemap
- Profile + notifications forms get autocomplete="off" + data-lpignore +
  data-1p-ignore at form and field level to keep password managers from
  popping open on /einstellungen; immomio_password uses autocomplete=new-password

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/static/map.js

@@ -79,13 +79,6 @@ function buildMap(el) {
     subdomains: "abcd",
     maxZoom: 19,
   }).addTo(mapInstance);
-  // Transit overlay — OpenRailwayMap highlights S-/U-/Tram-Linien.
-  L.tileLayer("https://{s}.tiles.openrailwaymap.org/standard/{z}/{x}/{y}.png", {
-    attribution: "© OpenRailwayMap",
-    subdomains: "abc",
-    maxZoom: 19,
-    opacity: 0.75,
-  }).addTo(mapInstance);
   markerLayer = L.layerGroup().addTo(mapInstance);
 }