Refactor geo cache persistence into repository + remove raw SQL from tasks/main, update task list

backend/app/tasks/geo_re_resolve.py

@@ -49,12 +49,7 @@ async def _run_re_resolve(app: Any) -> None:
     http_session = app.state.http_session
 
     # Fetch all IPs with NULL country_code from the persistent cache.
-    unresolved_ips: list[str] = []
-    async with db.execute(
-        "SELECT ip FROM geo_cache WHERE country_code IS NULL"
-    ) as cursor:
-        async for row in cursor:
-            unresolved_ips.append(str(row[0]))
+    unresolved_ips = await geo_service.get_unresolved_ips(db)
 
     if not unresolved_ips:
         log.debug("geo_re_resolve_skip", reason="no_unresolved_ips")