fix: rate limit behaviour for multi-channel spam

[theetrain]

Problem

• members rapidly posting 3+ messages within a 10-second period in a single channel were incorrectly flagged as multi-channel spam attempts because the rate limit on the messages alone would short-circuit the logic and not check for multi-channel spam.
  

  discord-bot/src/utils/ratelimit.ts

  Lines 33 to 41 in 3cf765e

  	if (available_uses > 0 && channels.size < this.unique_channels) {
  	if (consume) {
  	this.available_uses.set(key, {
  	limit: available_uses - 1,
  	channel_ids: channels.add(channelId),
  	});
  	}
  	return false;
  	}

• Those members were timed out as a result.
  

  discord-bot/src/events/on_message/_spam_filter.ts

  Lines 96 to 103 in 3cf765e

  	// Timeout
  	await Promise.allSettled([
  	timeout(member, 43_200_000, 'Multi-channel spam'),
  	mod_log(
  	message.client,
  	`User ${userMention(message.author.id)} was suspected of spamming and was timed out.`,
  	),
  	]);

Solution

• adjust rate limit logic to correctly detect multi-channel usage
• remove timeout for now, so we can opt back in via an environment variable. For now, mutli-channel-spam is logged to moderators.

Todos

• Fix multi-channel spam rate limit detection
• Remove timeout on multi-channel spam
• Add unit test
• Add config flag to timeout on multi channel spam

[theetrain]

This entire file underwent a big refactor to be more config-based (and eventually, CMS-config-based).

One important change is here; to only log multi channel spam attempts rather than time out.

[theetrain]

And here's the important fix, from && to || so that unique channel checks can be made without short-circuiting.

[theetrain]

This will probably cause a memory leak.

[theetrain]

Addressed: https://github.com/sveltejs/discord-bot/pull/86/changes/998792bff45bbc88192b9e4cdfcf0779e7ebfe24..1b4a305ae655bd7f5c11f964d6a212efb3d9e915