Add .env configuration for easy environment customization

- Create .env.example with all configurable settings:
  - Server IPs (RU_VDS_IP, DE_VDS_IP)
  - WireGuard ports (WG_CLIENT_PORT, WG_TUNNEL_PORT)
  - VPN networks (USER_VPN_NETWORK, TUNNEL_NETWORK)
  - DNS settings, SSH port, timeouts
- Add .gitignore to exclude .env from version control
- Update setup-ru-vds.sh to read from .env
- Update setup-de-vds.sh to read from .env
- Update add-client.sh to use configuration
- Setup scripts save config to /etc/wireguard/vpn.conf for runtime use
- Update documentation with .env usage instructions

This allows easy deployment to test environments by simply
changing values in .env before running setup scripts.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

scripts/add-client.sh

@@ -3,6 +3,24 @@ set -e
 
 # Script to add a new VPN client
 # Usage: ./add-client.sh <client_name>
+#
+# Configuration is loaded from .env file or /etc/wireguard/vpn.conf
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# Try to load from .env in project directory (for development)
+if [ -f "${SCRIPT_DIR}/../.env" ]; then
+    source "${SCRIPT_DIR}/../.env"
+# Or from deployed config
+elif [ -f "/etc/wireguard/vpn.conf" ]; then
+    source "/etc/wireguard/vpn.conf"
+fi
+
+# Default values
+: "${RU_VDS_IP:=176.124.216.197}"
+: "${WG_CLIENT_PORT:=51820}"
+: "${USER_VPN_GATEWAY:=10.10.0.1}"
+: "${WG_KEEPALIVE:=25}"
 
 if [ "$EUID" -ne 0 ]; then
     echo "ERROR: Please run as root"
@@ -29,8 +47,11 @@ fi
 echo "Adding new VPN client: ${CLIENT_NAME}"
 echo ""
 
+# Extract network prefix from gateway IP (e.g., 10.10.0 from 10.10.0.1)
+NETWORK_PREFIX=$(echo "$USER_VPN_GATEWAY" | sed 's/\.[0-9]*$//')
+
 # Find next available IP
-USED_IPS=$(wg show ${WG_INTERFACE} allowed-ips 2>/dev/null | grep -oP '10\.10\.0\.\K[0-9]+' | sort -n)
+USED_IPS=$(wg show ${WG_INTERFACE} allowed-ips 2>/dev/null | grep -oP "${NETWORK_PREFIX//./\\.}\.\K[0-9]+" | sort -n)
 NEXT_IP=2
 for ip in $USED_IPS; do
     if [ $ip -ge $NEXT_IP ]; then
@@ -39,11 +60,11 @@ for ip in $USED_IPS; do
 done
 
 if [ $NEXT_IP -gt 254 ]; then
-    echo "ERROR: No available IPs in 10.10.0.0/24 range"
+    echo "ERROR: No available IPs in ${NETWORK_PREFIX}.0/24 range"
     exit 1
 fi
 
-CLIENT_IP="10.10.0.${NEXT_IP}"
+CLIENT_IP="${NETWORK_PREFIX}.${NEXT_IP}"
 
 echo "[1/5] Generating client keys..."
 wg genkey | tee "${KEYS_DIR}/client_${CLIENT_NAME}.key" | wg pubkey > "${KEYS_DIR}/client_${CLIENT_NAME}.pub"
@@ -66,13 +87,13 @@ cat > "${CLIENTS_DIR}/${CLIENT_NAME}.conf" << EOF
 [Interface]
 PrivateKey = ${CLIENT_PRIVATE_KEY}
 Address = ${CLIENT_IP}/32
-DNS = 10.10.0.1
+DNS = ${USER_VPN_GATEWAY}
 
 [Peer]
 PublicKey = ${SERVER_PUBLIC_KEY}
-Endpoint = 176.124.216.197:51820
+Endpoint = ${RU_VDS_IP}:${WG_CLIENT_PORT}
 AllowedIPs = 0.0.0.0/0
-PersistentKeepalive = 25
+PersistentKeepalive = ${WG_KEEPALIVE}
 EOF
 
 chmod 600 "${CLIENTS_DIR}/${CLIENT_NAME}.conf"