feat(installer): add WireGuard check + auto-install for native install

nexusguard-install.sh

@@ -49,6 +49,7 @@ Prerequisites:
     - nginx installed and running
     - PostgreSQL installed and running
     - Redis installed and running
+    - WireGuard tools (will be auto-installed if missing)
     - Pre-built binaries in ./bin/ directory
 
 This script will:
@@ -90,6 +91,29 @@ command -v systemctl >/dev/null 2>&1 || error "systemctl is not installed"
 command -v psql >/dev/null 2>&1 || error "PostgreSQL client (psql) is not installed"
 command -v redis-cli >/dev/null 2>&1 || error "Redis client (redis-cli) is not installed"
 
+# Check and install WireGuard
+if ! command -v wg >/dev/null 2>&1; then
+    warn "WireGuard tools not found. Installing..."
+    if command -v apt >/dev/null 2>&1; then
+        apt update -qq && apt install -y -qq wireguard-tools
+    elif command -v dnf >/dev/null 2>&1; then
+        dnf install -y -q wireguard-tools
+    elif command -v yum >/dev/null 2>&1; then
+        yum install -y -q wireguard-tools
+    elif command -v pacman >/dev/null 2>&1; then
+        pacman -S --noconfirm wireguard-tools
+    else
+        error "Cannot auto-install WireGuard. Please install wireguard-tools manually."
+    fi
+    info "WireGuard tools installed: $(wg --version)"
+fi
+
+# Check WireGuard kernel module
+if ! lsmod 2>/dev/null | grep -q wireguard; then
+    warn "WireGuard kernel module not loaded. Loading..."
+    modprobe wireguard 2>/dev/null || warn "Could not load wireguard module (may need manual load or reboot)"
+fi
+
 # Check for pre-built binaries
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 SERVER_BINARY="$SCRIPT_DIR/bin/server-core"