Wetter-Chip auf Karte + Bugfix private Routen zählen für km-Stats

- GET /api/weather?lat=&lon= (Open-Meteo, 30-min TTL-Cache)
- Zecken-Warnung regelbasiert: März–Okt + Temp > 7°C
- Karte: Wetterchip oben rechts nach GPS-Fix
- stats.py + achievements.py: is_public-Filter entfernt —
  private Routen zählen jetzt für eigene km/Achievements
- SW by-v320, APP_VER 308

backend/main.py

@@ -119,6 +119,7 @@ from routes.stats          import router as stats_router
 from routes.achievements   import router as achievements_router
 from routes.training       import router as training_router
 from routes.praise         import router as praise_router
+from routes.weather        import router as weather_router
 
 app.include_router(auth_router,       prefix="/api/auth",       tags=["Auth"])
 app.include_router(dogs_router,       prefix="/api/dogs",       tags=["Hunde"])
@@ -134,6 +135,7 @@ app.include_router(walks_router,      prefix="/api/walks",      tags=["Gassi-Tre
 app.include_router(events_router,     prefix="/api/events",     tags=["Events"])
 app.include_router(sitting_router,    prefix="/api/sitting",    tags=["Sitting"])
 app.include_router(osm_router,        prefix="/api/osm",        tags=["OSM"])
+app.include_router(weather_router,    prefix="/api/weather",    tags=["Wetter"])
 app.include_router(forum_router,      prefix="/api/forum",      tags=["Forum"])
 app.include_router(lost_router,       prefix="/api/lost",       tags=["Verlorener Hund"])
 app.include_router(knigge_router,     prefix="/api/knigge",     tags=["Knigge"])