fix(geocode): accurate street name + always shows on dashboard

- Cache key uses 4 decimal places (~11m) instead of 3 (~111m) for correct street
- Dashboard geocodes on first GPS fix, then again every >50m moved (throttled 15s)
- Removed stale console.log

Co-authored-by: Copilot <[email protected]>

app.py

@@ -93,10 +93,10 @@ import functools
 import urllib.request
 
 @functools.lru_cache(maxsize=512)
-def _geocode_cached(lat3, lon3):
+def _geocode_cached(lat4, lon4):
     """Try Nominatim first (street-level), fall back to reverse_geocoder (city)."""
-    lat = lat3 / 1000.0
-    lon = lon3 / 1000.0
+    lat = lat4 / 10000.0
+    lon = lon4 / 10000.0
     try:
         url = f"https://nominatim.openstreetmap.org/reverse?format=jsonv2&lat={lat}&lon={lon}&accept-language=en"
         req = urllib.request.Request(url, headers={"User-Agent": "yaris-obd/1.0"})
@@ -126,7 +126,7 @@ def geocode_route():
     except (KeyError, ValueError):
         return jsonify(error="lat and lon required"), 400
     # Round to 3 decimals (~111m precision) for cache key
-    label = _geocode_cached(round(lat, 3) * 1000 // 1, round(lon, 3) * 1000 // 1)
+    label = _geocode_cached(int(round(lat, 4) * 10000), int(round(lon, 4) * 10000))
     return jsonify(label=label)
 
 @app.route('/api/dash/devices')