fix: report unsupported Tun state for systemd-user backend

Author: wnlen

README.md

@@ -82,7 +82,6 @@ bash install.sh
   clashctl log/logs  📜 查看日志
 
 💡 显示更多帮助命令：clashctl -h
-💡 更多高级能力：clashctl help advanced
 ```
 
 ------

scripts/core/clashctl.sh

@@ -4872,8 +4872,11 @@ doctor_tun_checks() {
   process_cap_rc=2
   case "$backend" in
     systemd|systemd-user)
-      tun_process_has_cap_net_admin "$backend" >/dev/null 2>&1
-      process_cap_rc=$?
+      if tun_process_has_cap_net_admin "$backend" >/dev/null 2>&1; then
+        process_cap_rc=0
+      else
+        process_cap_rc=$?
+      fi
       ;;
   esac
 
@@ -5342,8 +5345,11 @@ tun_doctor_primary_reason() {
   process_cap_rc=2
   case "$backend" in
     systemd|systemd-user)
-      tun_process_has_cap_net_admin "$backend" >/dev/null 2>&1
-      process_cap_rc=$?
+      if tun_process_has_cap_net_admin "$backend" >/dev/null 2>&1; then
+        process_cap_rc=0
+      else
+        process_cap_rc=$?
+      fi
       ;;
   esac