feat: add IP geolocation tracking and include location in prompts

- Add GeoLite2-City.mmdb database for IP lookup
- Create geoip.py module for IP location services
- Extract client IP from requests and log location info
- Pass location context to LLM prompts for enhanced responses

backend/geoip.py

@@ -0,0 +1,56 @@
+import os
+import logging
+from typing import Optional
+
+logger = logging.getLogger("api")
+
+_geoip_reader = None
+
+
+def _get_reader():
+    global _geoip_reader
+    if _geoip_reader is not None:
+        return _geoip_reader
+    try:
+        import geoip2.database
+        db_path = os.path.join(os.path.dirname(__file__), "GeoLite2-City.mmdb")
+        if os.path.exists(db_path):
+            _geoip_reader = geoip2.database.Reader(db_path)
+            logger.info("GeoIP database loaded: %s", db_path)
+            return _geoip_reader
+        else:
+            logger.warning("GeoIP database not found: %s", db_path)
+    except ImportError:
+        logger.warning("geoip2 not installed, IP location disabled")
+    except Exception as e:
+        logger.warning("Failed to load GeoIP database: %s", e)
+    return None
+
+
+def get_ip_location(ip: str) -> Optional[dict]:
+    if not ip or ip in ("127.0.0.1", "localhost", "::1"):
+        return None
+    reader = _get_reader()
+    if not reader:
+        return None
+    try:
+        response = reader.city(ip)
+        country = response.country.name
+        region = response.subdivisions.most_specific.name if response.subdivisions else None
+        city = response.city.name
+        parts = [p for p in [country, region, city] if p]
+        if not parts:
+            return None
+        return {
+            "country": country,
+            "region": region,
+            "city": city,
+            "display": " ".join(parts)
+        }
+    except Exception:
+        return None
+
+
+def get_ip_location_text(ip: str) -> str:
+    loc = get_ip_location(ip)
+    return loc["display"] if loc else ""