fix: initialize missing MasterOptions fields in master.follower (#7808)

Fix nil pointer dereference panic when starting master.follower.

The init() function was missing initialization for:
- maxParallelVacuumPerServer
- telemetryUrl
- telemetryEnabled

These fields are dereferenced in toMasterOption() causing a panic.

Fixes #7806

weed/command/master_follower.go

@@ -41,6 +41,9 @@ func init() {
 	mf.metricsAddress = aws.String("")
 	mf.metricsIntervalSec = aws.Int(0)
 	mf.raftResumeState = aws.Bool(false)
+	mf.maxParallelVacuumPerServer = aws.Int(1)
+	mf.telemetryUrl = aws.String("")
+	mf.telemetryEnabled = aws.Bool(false)
 }
 
 var cmdMasterFollower = &Command{