feat: add geolocation fields to session and implement geo stats endpoint

- Added country, city, countryCode, latitude, and longitude fields to the Session model.
- Updated geoip service to fetch and store geolocation data based on user IP.
- Created a new admin endpoint to retrieve geolocation statistics, including user counts by country and city.
- Enhanced admin page to display geolocation statistics with expandable city details.
- Introduced caching for geolocation data to optimize performance.

apps/backend/src/middlewares/require-auth.middleware.ts

@@ -1,7 +1,20 @@
 import { auth } from '@/lib/auth';
+import { fetchGeoInfo } from '@/lib/geoip';
+import { db } from '@/lib/prisma';
 import type { AppEnv } from '@/types/hono';
 import { createMiddleware } from 'hono/factory';
 
+type SessionWithGeo = {
+  id: string;
+  ipAddress: string | null;
+  userAgent: string | null;
+  country: string | null;
+  city: string | null;
+  countryCode: string | null;
+  latitude: number | null;
+  longitude: number | null;
+};
+
 export const requireAuth = createMiddleware<AppEnv>(async (c, next) => {
   const session = await auth.api.getSession({
     headers: c.req.raw.headers,
@@ -23,8 +36,33 @@ export const requireAuth = createMiddleware<AppEnv>(async (c, next) => {
     );
   }
 
+  const s = session.session as unknown as SessionWithGeo;
+
   c.set('user', session.user);
   c.set('session', session.session);
 
+  if (s.ipAddress && !s.country) {
+    resolveSessionGeo(s.id, s.ipAddress);
+  }
+
   await next();
 });
+
+async function resolveSessionGeo(sessionId: string, ipAddress: string) {
+  try {
+    const geo = await fetchGeoInfo(ipAddress);
+    if (!geo) return;
+    await db.session.update({
+      where: { id: sessionId },
+      data: {
+        country: geo.country,
+        city: geo.city,
+        countryCode: geo.countryCode,
+        latitude: geo.lat,
+        longitude: geo.lon,
+      },
+    });
+  } catch {
+    // Silently fail — geo enrichment is best-effort
+  }
+}