Kernel messages (dmesg) source read from /dev/kmsg

New source in Settings > Sources, off by default: reads the kernel ring
buffer of the host through /dev/kmsg, dates records from the boot time and
resumes after the last sequence number of the same boot (no duplicates on
restart). Missing device or denied access is shown in the UI, retried every
10 s. docker-compose.yml and .env.example document the device and the
kernel.dmesg_restrict / CAP_SYSLOG options.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

syslog.go

@@ -36,7 +36,7 @@ type Entry struct {
 	Proto    string // udp or tcp
 	HostIP   string // original host value when it was an IP resolved through DNS
 
-	SourceType string            // "syslog" or "docker"
+	SourceType string            // "syslog", "docker", "host" or "kernel"
 	Extra      map[string]string // additional fields (docker: container, image, …)
 
 	// Not stored. Wait: the producer can be slowed down when the queue is full