Add Arch Linux server support and fix package sanitization

- Add Arch Linux (pacman) support to server operations: CheckUpdates, InstallDocker, InstallPrerequisites, UpdatePackage
- Implement parsePacmanOutput() to parse 'pacman -Qu' output format
- Add security improvement: package name sanitization to prevent command injection
- Initialize variables in CheckUpdates to prevent undefined variable errors in catch block
- Use proper Arch pacman flags: -Syu for full system upgrade before operations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/Actions/Server/InstallDocker.php

@@ -78,6 +78,8 @@ class InstallDocker
                 $command = $command->merge([$this->getRhelDockerInstallCommand()]);
             } elseif ($supported_os_type->contains('sles')) {
                 $command = $command->merge([$this->getSuseDockerInstallCommand()]);
+            } elseif ($supported_os_type->contains('arch')) {
+                $command = $command->merge([$this->getArchDockerInstallCommand()]);
             } else {
                 $command = $command->merge([$this->getGenericDockerInstallCommand()]);
             }
@@ -150,4 +152,14 @@ class InstallDocker
     {
         return "curl https://releases.rancher.com/install-docker/{$this->dockerVersion}.sh | sh || curl https://get.docker.com | sh -s -- --version {$this->dockerVersion}";
     }
+
+    private function getArchDockerInstallCommand(): string
+    {
+        // Use -Syu to perform full system upgrade before installing Docker
+        // Partial upgrades (-Sy without -u) are discouraged on Arch Linux
+        // as they can lead to broken dependencies and system instability
+        return 'pacman -Syu --noconfirm docker docker-compose && '.
+            'systemctl enable docker.service && '.
+            'systemctl start docker.service';
+    }
 }