Einzelbeleg: CI poi pin from the receipt address, plus a centre button

The station marker was a red circleMarker. It is now the CI poi pin
(poi-l/poi-s via tankstellenMarkerSVG) - the plain pin rather than poi-car, so
the vehicle and the station stay distinguishable on a map.

While testing it turned out nothing in the backend ever writes station_lat /
station_lon, so that marker had never been reachable in practice. The receipt
address is now geocoded in the frontend via Nominatim /search
(adresseAufloesen, the forward counterpart to the existing reverse lookup),
with results cached in localStorage - negative ones too, since a station
address does not move and Nominatim's terms ask for caching. Verified live:
"Shell, SÖLDEN" resolves to 46.9756 / 11.0111.

The map card gained a centre button (CI.gps, which is byte-identical to the
delivered gps-s.svg), disabled until the coordinates arrive. .mapbox needed
position:relative so the control anchors to the card instead of an ancestor.
Only in the Einzelbeleg, as requested - the Standort fullscreen already has
its own centre controls.

Co-Authored-By: Claude Opus 5 <[email protected]>

homeassistant/www/audi-dashboard.css

@@ -688,7 +688,10 @@ button.tile, .tilebtn { transition: background .15s, transform .1s; }
 .swipe-wrap.swiped .swipe-content { transform: translateX(-84px); }
 
 /* -------------------------------------------------------------- Karte */
-.mapbox { border-radius: var(--r-tile); overflow: hidden; height: 210px; background: var(--tile); }
+/* position:relative, damit der Zentrieren-Knopf im Einzelbeleg (absolut
+   positioniert, siehe .kartensteuerung-klein) sich an dieser Kachel ausrichtet
+   und nicht am naechsten Vorfahren weiter oben. */
+.mapbox { position: relative; border-radius: var(--r-tile); overflow: hidden; height: 210px; background: var(--tile); }
 .mapbox #map { width: 100%; height: 100%; }
 
 /* --------------------------------------------------------- Standort
@@ -757,6 +760,12 @@ button.tile, .tilebtn { transition: background .15s, transform .1s; }
 }
 .kartensteuerung button:active { transform: scale(.94); }
 :host([data-theme="tag"]) .kartensteuerung button:active { background: #fff; }
+/* Variante in der Belegkarte: die Karte ist dort nur 210px hoch, ein 48er-
+   Knopf mit 16px Abstand wuerde ein Viertel davon verdecken. */
+.kartensteuerung-klein { top: 10px; right: 10px; }
+.kartensteuerung-klein button { width: 36px; height: 36px; }
+.kartensteuerung-klein button:disabled { opacity: .45; cursor: default; }
+.kartensteuerung-klein button:disabled:active { transform: none; }
 
 /* Sichtbarer Anteil im geschlossenen Zustand (STANDORT_PEEK_PX im Frontend) -
    beide Werte müssen zusammenpassen, siehe Kommentar dort. Der Rest des