feat(config): add restart options for unit configuration

* include Restart, RestartSec, and RestartRetries fields
* update service file generation to support restart settings
* add tests for restart behavior in unit generation

config/config.go

@@ -20,6 +20,9 @@ type Unit struct {
 	Delay          string `yaml:"delay,omitempty"` // e.g. "5s"
 	Enabled        bool   `yaml:"enabled"`
 	DisabledReason string `yaml:"disabled_reason,omitempty"`
+	Restart        bool   `yaml:"restart,omitempty"`         // enable Restart=on-failure
+	RestartSec     int    `yaml:"restart_sec,omitempty"`     // seconds between restarts
+	RestartRetries int    `yaml:"restart_retries,omitempty"` // max restart attempts (StartLimitBurst)
 }
 
 // Config is the root config structure.