Round 3 fixes: cancelled polling, aggregator invalid_count, filter state, scheduler atomicity, HTTP exception handler, tests

app/repositories/proxy_repo.py

@@ -124,9 +124,10 @@ class ProxyRepository:
     async def batch_delete(db: aiosqlite.Connection, proxies: List[Tuple[str, int]]) -> int:
         if not proxies:
             return 0
+        changes_before = db.total_changes
         await db.executemany("DELETE FROM proxies WHERE ip = ? AND port = ?", proxies)
         await db.commit()
-        return len(proxies)
+        return db.total_changes - changes_before
 
     @staticmethod
     async def get_by_ip_port(