Navigation, Karten-FABs, Nearby-Alerts

- Bottom-Nav neu: Karte | Routen | + | Tagebuch | Forum
- + reduziert auf: Giftköder, Gassi-Treffen, Verlorener Hund
- Notification-Badge auf User-Avatar (Header)
- Nearby-Alerts: Nav-Leiste pulsiert rot/orange bei Giftköder/vermisstm Hund in 20km
- SW postMessage bei poison/lost_alert → sofortiger Alert-Check
- Karten-FABs: nur Marker setzen + Standort (Route aufzeichnen + Offline entfernt)
- SW by-v272, APP_VER 262

backend/routes/alerts.py

@@ -0,0 +1,36 @@
+"""BAN YARO — Nearby Alerts (Giftköder + Vermisste Hunde)"""
+import math
+from datetime import datetime
+from fastapi import APIRouter
+
+from database import db
+
+router = APIRouter()
+
+_RADIUS_M = 20_000  # 20 km
+
+
+def _haversine(lat1: float, lon1: float, lat2: float, lon2: float) -> float:
+    R = 6_371_000
+    p1, p2 = math.radians(lat1), math.radians(lat2)
+    dp = math.radians(lat2 - lat1)
+    dl = math.radians(lon2 - lon1)
+    a = math.sin(dp / 2) ** 2 + math.cos(p1) * math.cos(p2) * math.sin(dl / 2) ** 2
+    return 2 * R * math.asin(math.sqrt(a))
+
+
+@router.get("")
+async def nearby_alerts(lat: float, lon: float):
+    now = datetime.utcnow().isoformat()
+    with db() as conn:
+        poisons = conn.execute(
+            "SELECT lat, lon FROM poison WHERE geloest=0 AND expires_at > ?", (now,)
+        ).fetchall()
+        lost = conn.execute(
+            "SELECT lat, lon FROM lost_dogs WHERE is_active=1"
+        ).fetchall()
+
+    has_poison = any(_haversine(lat, lon, r["lat"], r["lon"]) <= _RADIUS_M for r in poisons)
+    has_lost   = any(_haversine(lat, lon, r["lat"], r["lon"]) <= _RADIUS_M for r in lost)
+
+    return {"poison": has_poison, "lost": has_lost}