Add support for root account execution without sudo

- Update script comments and documentation for root vs regular users
- Improve error message for missing root privileges
- Add separate command examples for root accounts (Proxmox, containers, etc.)
- Update README and installation guide with both sudo and non-sudo examples

🚀 Generated with Claude Code

Co-Authored-By: Claude <noreply@anthropic.com>

QUICK_INSTALL_GUIDE.md

@@ -6,12 +6,20 @@
 
 ### 방법 1: curl 사용 (권장)
 ```bash
+# 일반 사용자 계정에서
 curl -fsSL https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | sudo bash
+
+# root 계정에서 (Proxmox, Docker 컨테이너 등)
+curl -fsSL https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | bash
 ```
 
 ### 방법 2: wget 사용
 ```bash
+# 일반 사용자 계정에서
 wget -qO- https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | sudo bash
+
+# root 계정에서
+wget -qO- https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | bash
 ```
 
 ### 방법 3: 스크립트 다운로드 후 실행
@@ -23,8 +31,11 @@ sudo ./quick-install.sh
 
 ### 방법 4: 기존 Tailscale 연결이 있는 경우 (강제 재등록)
 ```bash
-# 기존 Tailscale/Headscale 연결을 강제로 해제하고 재등록
+# 일반 사용자 계정에서
 curl -fsSL https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | sudo bash -s -- --force
+
+# root 계정에서 (Proxmox 등)
+curl -fsSL https://git.0bin.in/thug0bin/headscale-tailscale-replacement/raw/branch/feature/working-headscale-setup/quick-install.sh | bash -s -- --force
 ```
 
 ### 방법 5: 스크립트 옵션 확인