Add pacman support for Arch Linux systems

- Detect netbird installed via pacman
- Remove netbird packages using pacman -Rns when replacing with binary install
- Update README to document pacman support

netbird-install-update/README.md

@@ -166,7 +166,7 @@ The `--password` option provides a default sudo password for remote deployments.
 The script detects three installation states:
 
 1. **Not Installed**: Netbird binary not found in PATH
-2. **Package Manager Install**: Installed via apt, yum, dnf, zypper, or rpm-ostree
+2. **Package Manager Install**: Installed via apt, yum, dnf, zypper, pacman, or rpm-ostree
 3. **Binary Install**: Installed via the official curl-based installer
 
 Detection is performed by:
@@ -405,6 +405,7 @@ Failed Hosts:
 - yum (RHEL/CentOS 7)
 - dnf (Fedora/RHEL 8+/CentOS 8+)
 - zypper (openSUSE)
+- pacman (Arch Linux)
 - rpm-ostree (Fedora Silverblue)
 
 ### SELinux Support