stoatchat before 20250210-1 Unrestricted Message History Fetch

stoatchat (delta) versions before 20250210-1 (0.8.2) contain a logic error in the query messages route. When fetching messages 'nearby' another message, the database query can be given a message limit of zero, which the database interprets as 'no limit'. A remote unauthenticated attacker can craft nearby message fetch requests to download an entire channel's message history in a single expensive request, and can send many such requests in parallel, resulting in denial of service through resource exhaustion.