feat: add wireguard secure installer with modular architecture

This commit introduces a new WireGuard VPN installer with enterprise-grade security features. The installer includes:

- Zero-touch installation with automatic configuration
- Modular architecture for maintainability (separate lib files)
- Client management interface with bandwidth monitoring
- Support for multiple Linux distributions
- Secure defaults and hardened configurations

The implementation provides a complete solution for deploying WireGuard VPN servers with minimal user interaction while maintaining security best practices.

install.sh

@@ -0,0 +1,52 @@
+#!/bin/bash
+# WireGuard Secure Installer
+# Copyright (c) 2025 Muhammad Fadhila Abiyyu Faris
+# GitHub: [github.com/fadhila36/wireguard-secure-installer](https://github.com/fadhila36/wireguard-secure-installer)
+
+# Set strict mode
+set -e
+
+# Load Config and Libraries
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/config.env"
+source "$SCRIPT_DIR/lib/utils.sh"
+source "$SCRIPT_DIR/lib/network.sh"
+source "$SCRIPT_DIR/lib/os_detect.sh"
+source "$SCRIPT_DIR/lib/wg_core.sh"
+
+# Trap for cleanup
+trap cleanup EXIT
+
+# Main Logic
+main() {
+    check_root
+    show_banner
+    
+    log_info "Starting Zero-Touch Installation..."
+    
+    check_os
+    install_dependencies
+    
+    detect_main_interface
+    detect_public_ip
+    
+    configure_firewall
+    
+    generate_keys
+    generate_server_config
+    start_wireguard
+    
+    # Create default admin client (IP .2) if not exists
+    if ! grep -q "### Client: $CLIENT_NAME" "$WG_CONFIG"; then
+        create_client_config "$CLIENT_NAME" "2"
+    else
+        log_info "Default client '$CLIENT_NAME' already exists. Skipping creation."
+    fi
+    
+    log_info "Installation Completed Successfully!"
+    echo -e "${GREEN}WireGuard is installed and running.${NC}"
+    echo -e "Client Config: ${YELLOW}$INSTALL_DIR/clients/$CLIENT_NAME.conf${NC}"
+    echo -e "Manage script: ${YELLOW}$INSTALL_DIR/manage.sh${NC}"
+}
+
+main