docs: integration events (#7670)

https://linear.app/unleash/issue/2-2444/write-documentation-on-integration-events

Adds documentation for integration events.

Should be pretty straightforward, so a section in the existing
integrations reference doc should be good enough.

See it here:
https://unleash-docs-git-docs-integration-events-unleash-team.vercel.app/reference/integrations#integration-events

website/docs/reference/integrations/integrations.md

@@ -47,6 +47,55 @@ Our wonderful community has also created the following integrations:
 - [Quarkus](https://github.com/quarkiverse/quarkus-unleash)
 - [Vue Unleash plugin](https://github.com/crishellco/vue-unleash)
 
+## Integration events
+
+:::info Availability
+
+Integration events were introduced as a beta feature in **Unleash 6.1**.
+
+:::
+
+Integration events in Unleash provide a streamlined way to debug integrations by logging their executions and offering a visual interface for administrators to monitor these events. This feature enhances visibility into the functioning of various integrations, helping to quickly identify and resolve issues.
+
+Integration events are logged for all outgoing integrations configured in Unleash. This includes integrations that send information from Unleash to other systems. Currently supported integrations include:
+
+ - [Datadog](./datadog.md)
+ - [Microsoft Teams](./teams.md)
+ - New Relic
+ - [Slack (deprecated)](./slack.md)
+ - [Slack App](./slack-app.md)
+ - [Webhook](./webhook.md)
+
+### Viewing integration events
+
+:::info Permissions
+
+Viewing integration events requires the `ADMIN` permission.
+
+:::
+
+On the Integrations page, administrators will notice a new icon at the bottom right of each integration card. This icon indicates the status of the latest integration event:
+
+ - **Green Check Mark**: The event was successful.
+ - **Red Exclamation Mark**: The event failed.
+ - **Yellow Exclamation Mark**: The event encountered some errors.
+
+Hovering over this icon provides more detailed information about the event. If the icon is not visible, it might be because the integration has not executed yet.
+
+![Icon representing the latest integration event for a specific integration configuration.](/img/integration-events/integration-events-latest.png)
+
+Administrators will also find a new "View events" option in the action menu of the integration cards. Selecting this option displays a list of the latest events, sorted from most recent to oldest. Clicking on an event in the list will display its details on the right side.
+
+Each integration event's detailed view includes comprehensive information about the event's status. This helps administrators investigate and troubleshoot issues effectively. The detailed view encompasses:
+
+ - Details about the integration execution result, which vary depending on the integration. For example, this might include HTTP response status codes from the requests made by the integration.
+ - The underlying Unleash event that triggered the integration, which can be expanded to show detailed information.
+ - Specific details about the integration execution, which vary depending on the integration. For example, Slack integrations show the message that was sent and the target channels.
+
+Unleash retains only the most recent event for each integration configuration, along with the last 100 events from the past two hours. All other events are automatically deleted.
+
+![Integration events view, with the sorted list on the left side and the detailed view on the right side.](/img/integration-events/integration-events-list-details.png)
+
 ## Notes {#notes}
 
 When updating or creating a new integration configuration it can take up to one minute before Unleash picks up the new config on all instances due to caching.