Refactor geo re-resolve to use geo_cache repo and move data-access out of router

backend/app/routers/geo.py

@@ -153,12 +153,7 @@ async def re_resolve_geo(
         that were retried.
     """
     # Collect all IPs in geo_cache that still lack a country code.
-    unresolved: list[str] = []
-    async with db.execute(
-        "SELECT ip FROM geo_cache WHERE country_code IS NULL"
-    ) as cur:
-        async for row in cur:
-            unresolved.append(str(row[0]))
+    unresolved = await geo_service.get_unresolved_ips(db)
 
     if not unresolved:
         return {"resolved": 0, "total": 0}