feat: add healthchecks section to self host

mint.json

@@ -353,6 +353,7 @@
             "self-hosting/lifecycle-maintenance",
             "self-hosting/lifecycle-maintenance/securing-your-deployment",
             "self-hosting/lifecycle-maintenance/server-specs",
+            "self-hosting/lifecycle-maintenance/healthchecks",
             "self-hosting/lifecycle-maintenance/telemetry"
           ]
         },

self-hosting/lifecycle-maintenance/healthchecks.mdx

@@ -0,0 +1,29 @@
+---
+title: "Healthchecks"
+---
+
+<Info>
+  This requires the Docker image to be `journeyapps/powersync-service:0.5.8` or later.
+</Info>
+
+The following endpoints can be used to check your system:
+
+### Startup:
+
+You can use the `/probes/startup` endpoint to confirm the service has started up correctly.
+
+A `200` status code shows the system has started up.
+
+A `400` status code shows the system has **not** yet started.
+
+### Liveness:
+
+You can use the `/probes/liveness` endpoint to confirm the service is alive.
+
+A `200` status code shows the system is alive.
+
+A `400` status code shows the system is **not** alive.
+
+<Tip>
+**Example**: An example configuration with Docker Compose is available in the [self-host-demo app](https://github.com/powersync-ja/self-host-demo/blob/main/services/powersync.yaml).
+</Tip>