Add doctor command (#1259)

* feat: doctor command

* doctor: use console.warn for quickshell feature logs

* doctor: show compositor, quickshell and cli path in verbose

* doctor: show useful env variables

* doctor: indicate if config files are readonly

* doctor: add power-profiles-daemon and i2c

* doctor: cleanup code

* doctor: fix icon theme env variable

* doctor: use builtin config/cache dir functions

* doctor: refactor to use DoctorStatus struct and 'enum'

* doctor: use network backend detector

core/internal/utils/exec.go

@@ -1,6 +1,9 @@
 package utils
 
-import "os/exec"
+import (
+	"os/exec"
+	"strings"
+)
 
 func CommandExists(cmd string) bool {
 	_, err := exec.LookPath(cmd)
@@ -15,3 +18,16 @@ func AnyCommandExists(cmds ...string) bool {
 	}
 	return false
 }
+
+func IsServiceActive(name string, userService bool) bool {
+	if !CommandExists("systemctl") {
+		return false
+	}
+
+	args := []string{"is-active", name}
+	if userService {
+		args = []string{"--user", "is-active", name}
+	}
+	output, _ := exec.Command("systemctl", args...).Output()
+	return strings.EqualFold(strings.TrimSpace(string(output)), "active")
+}