simplify plugin scheduler: remove configurable IdleSleepSeconds, use constant 61s

The SchedulerConfig struct and its persistence/API were unnecessary
indirection. Replace with a simple constant (reduced from 613s to 61s)
so the scheduler re-checks for detectable job types promptly after
going idle, improving the clean-install experience.

weed/admin/plugin/scheduler_config.go

@@ -2,30 +2,4 @@ package plugin
 
 import "time"
 
-const (
-	defaultSchedulerIdleSleep = 613 * time.Second
-)
-
-type SchedulerConfig struct {
-	IdleSleepSeconds int32 `json:"idle_sleep_seconds"`
-}
-
-func DefaultSchedulerConfig() SchedulerConfig {
-	return SchedulerConfig{
-		IdleSleepSeconds: int32(defaultSchedulerIdleSleep / time.Second),
-	}
-}
-
-func normalizeSchedulerConfig(cfg SchedulerConfig) SchedulerConfig {
-	if cfg.IdleSleepSeconds <= 0 {
-		return DefaultSchedulerConfig()
-	}
-	return cfg
-}
-
-func (c SchedulerConfig) IdleSleepDuration() time.Duration {
-	if c.IdleSleepSeconds <= 0 {
-		return defaultSchedulerIdleSleep
-	}
-	return time.Duration(c.IdleSleepSeconds) * time.Second
-}
+const defaultSchedulerIdleSleep = 61 * time.Second