routermon: break chunk loop early when circuit breaker fires

Stop sending further API requests mid-batch once the backoff is
triggered, saving remaining missing IPs as empty placeholders
immediately instead of waiting for them to timeout one-by-one.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

routermon/receiver.py

@@ -423,6 +423,16 @@ def _geo_worker_loop():
                                     _geo_consecutive_misses, _GEO_BACKOFF_SECS,
                                 )
                                 _geo_consecutive_misses = 0
+                                # Save remaining uncached IPs and stop the loop early.
+                                remaining = missing[i + 100:]
+                                if remaining:
+                                    IPGeoCache.objects.bulk_create(
+                                        [IPGeoCache(ip=ip) for ip in remaining
+                                         if ip not in geo_cache],
+                                        ignore_conflicts=True,
+                                    )
+                                    _geo_skip.update(remaining)
+                                break
                         elif results:
                             _geo_consecutive_misses = 0