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 <noreply@anthropic.com>

AGENTS.md

@@ -804,6 +804,38 @@ wraps the web app for iPhone; a PWA home-screen install is the accepted intermed
       un-ignoring. **Keep it in sync whenever `pyscript/` or `www/` changes** — that was already the
       working rule, but it is now visible in the repo when it is forgotten.
       Deployed to `audi_ha_test` (version `1786766000`).
+- [x] Fifth round the same day (2026-08-16) — one-click installer and the Einzelbeleg map:
+      (1) **`installationspaket/Installieren.cmd` + `install.ps1`** automate steps 1–3 of
+      `ANLEITUNG.md`. The `.cmd` wrapper exists because double-clicking a `.ps1` opens it in an
+      editor and the execution policy blocks it; the bypass is per-call, the machine policy is not
+      touched. Safe to re-run: never overwrites `fahrzeugprofil.json`, `fahrten.jsonl`,
+      `tankvorgaenge.jsonl`, `entitaeten.json`, `ha_token.txt`; backs `configuration.yaml` up to
+      `.bak` and replaces its own marker-delimited block instead of appending twice; refuses to
+      touch the file at all when `pyscript:`/`panel_custom:` are already there from another source
+      (duplicate top-level keys are invalid YAML — HA would not start); aborts before writing if
+      the target has no `configuration.yaml`. `-Pruefen` is a dry run. **`install.ps1` is stored
+      UTF-8 *with* BOM on purpose** — PowerShell 5.1 reads scripts as ANSI otherwise and mangles
+      every umlaut; the files it *writes* stay BOM-less (YAML). Verified against a fake config
+      tree: fresh install, re-run idempotency, data preservation, foreign-key refusal,
+      wrong-directory abort, and the merged YAML parses.
+      (2) **Tankstellenposition im Einzelbeleg.** The red `circleMarker` is now the CI `poi` pin
+      (`CI.poiL`/`CI.poiS` from `poi-l.svg`/`poi-s.svg`, via `tankstellenMarkerSVG()`) — deliberately
+      the plain pin, not `poi-car`, so vehicle and station stay distinguishable.
+      **Found while testing: nothing in the backend ever writes `station_lat`/`station_lon`**, so
+      this marker had never actually been reachable. Fixed by geocoding the receipt address in the
+      frontend (`adresseAufloesen()`, Nominatim `/search` — the forward counterpart to the existing
+      `standortAdresseAufloesen()`), with results cached in `localStorage` (`audi_dashboard_geocache`)
+      including negative results, since a station address does not move and Nominatim's terms ask
+      for caching. Confirmed live: `Shell, SÖLDEN` → 46.9756/11.0111.
+      (3) **Zentrieren-Knopf** in the Einzelbeleg map card (`mapBoxMitZentrieren()`, `CI.gps` —
+      byte-identical to the delivered `gps-s.svg`), disabled until the coordinates arrive. `.mapbox`
+      gained `position:relative` so the control anchors to the card. Only there, per explicit
+      request — the Standort fullscreen already has its own centre controls.
+      Deployed to `audi_ha_test` (version `1786769000`).
+      Note for testing map behaviour in this app: `initMap()` runs on **every** `render()`, and the
+      app re-renders on each backend push (~30 s), rebuilding the map and re-centring it. Panning
+      the map from the console and checking later therefore proves nothing — spy on
+      `L.Map.prototype.flyTo` instead.
 - [ ] Fix remaining documentation drift (statistics claim, README gaps, obsolete TODO comment) —
       text-only changes; INSTALL.md's WLAN/TommiG1 drift and stale variable names were fixed
       2026-08-12 (see section B); `DESIGN_REVIEW_2026-08-13.md` and `REVIEW_main_2026-08-13.md`