Reduce notification delay

[vmartinv]

Takes the time to block an address into sub-second territory.

A bouncer polls LAPI, every 10s by default. Pushing new bans to the firewall with a notification plugin (http plugin -> small endpoint that adds the IP to the bouncer's set) brings that down to ~1s, but no lower: with group_threshold set, the watcher only flushes on its 1s ticker, so every notification waits up to a second. This PR flushes as soon as the threshold is reached, so a ban reaches the firewall in well under a second.

The 6-alert burst in TestBrokerRunGroupThreshold used to be delivered as 4 + 2 because both batches landed before a tick; now the first 4 go out immediately, so the test sends 4 and expects one notification.

How it was tested

go test ./pkg/csplugin/ -race. The new TestPluginAlertCountWatcherFlushesImmediately fails without the change and passes with it.

Checklist

• One concern only.
• No break to LAPI/CAPI payloads, database schema, config keys, or cscli -o json|raw output.
• A human has reviewed this diff line by line.
• A human has tested this change, not only an agent.

AI assistance used: mostly

🤖 Generated with Claude Code

https://claude.ai/code/session_01XuiYfhB3KFGAAioDt2dPus

[github-actions]

@vmartinv: There are no 'kind' label on this PR. You need a 'kind' label to generate the release automatically.

• /kind feature
• /kind enhancement
• /kind refactoring
• /kind fix
• /kind chore
• /kind dependencies

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.

[github-actions]

@vmartinv: There are no area labels on this PR. You can add as many areas as you see fit.

• /area agent
• /area local-api
• /area cscli
• /area appsec
• /area security
• /area configuration

Details

I am a bot created to help the crowdsecurity developers manage community feedback and contributions. You can check out my manifest file to understand my behavior and what I can do. If you want to use this for your project, you can check out the BirthdayResearch/oss-governance-bot repository.