refactor: replace direct newService calls with ServiceCommand pattern

- Replace all direct newService() calls with ServiceCommand initialization
- Update command constructors to use ServiceCommand instead of ServiceManager
- Simplify LogCommand and UpgradeCommand structs by removing serviceManager field
- Remove unused global svcConfig variable from prog.go
- Improve consistency and centralize service creation logic

This change establishes a consistent pattern for service operations across
the codebase, making it easier to maintain and extend service-related
functionality.

cmd/cli/prog.go

@@ -79,13 +79,6 @@ var logf = func(format string, args ...any) {
 //lint:ignore U1000 use in newLoopbackOSConfigurator
 var noopLogf = func(format string, args ...any) {}
 
-var svcConfig = &service.Config{
-	Name:        ctrldServiceName,
-	DisplayName: "Control-D Helper Service",
-	Description: "A highly configurable, multi-protocol DNS forwarding proxy",
-	Option:      service.KeyValue{},
-}
-
 var useSystemdResolved = false
 
 type prog struct {