feat: Add real-time visitor map with IP geolocation

- Add latitude/longitude columns to visitor_logs model
- Update visitor_service to fetch and store coordinates from ip-api.com
- Add /admin/map-data API endpoint for map visualization
- Create VisitorMap component using Leaflet/OpenStreetMap
- Integrate map into visitor-stats admin page
- 30-second auto-refresh with animation for new visitors
- Color-coded markers (red: active, blue: recent)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/services/visitor_service.py

@@ -15,7 +15,7 @@ from sqlalchemy import func
 from ..models.visitor import VisitorLog, VisitorDailyStats, VisitorSession
 
 # IP Geolocation service (free, 45 req/min limit)
-IP_API_URL = "http://ip-api.com/json/{ip}?fields=status,country,countryCode,regionName,city"
+IP_API_URL = "http://ip-api.com/json/{ip}?fields=status,country,countryCode,regionName,city,lat,lon"
 
 # Cache for IP geolocation results (in-memory, simple)
 _geo_cache: Dict[str, Dict] = {}
@@ -77,7 +77,7 @@ async def get_geo_info(ip: str) -> Optional[Dict]:
     if ip.startswith(('127.', '192.168.', '10.', '172.16.', '172.17.', '172.18.', '172.19.',
                       '172.20.', '172.21.', '172.22.', '172.23.', '172.24.', '172.25.',
                       '172.26.', '172.27.', '172.28.', '172.29.', '172.30.', '172.31.', 'localhost', '::1')):
-        return {"country": "Local", "country_code": "LO", "region": "", "city": ""}
+        return {"country": "Local", "country_code": "LO", "region": "", "city": "", "latitude": None, "longitude": None}
 
     try:
         async with httpx.AsyncClient() as client:
@@ -94,6 +94,8 @@ async def get_geo_info(ip: str) -> Optional[Dict]:
                         "country_code": data.get("countryCode", ""),
                         "region": data.get("regionName", ""),
                         "city": data.get("city", ""),
+                        "latitude": data.get("lat"),
+                        "longitude": data.get("lon"),
                     }
                     # Cache the result
                     _geo_cache[ip] = result
@@ -165,6 +167,8 @@ async def log_visit(
         country_code=geo_info.get("country_code"),
         city=geo_info.get("city"),
         region=geo_info.get("region"),
+        latitude=geo_info.get("latitude"),
+        longitude=geo_info.get("longitude"),
         utm_source=utm_source,
         utm_medium=utm_medium,
         utm_campaign=utm_campaign,