feat: add web proxy target allowlist support via NEXAVPN_ALWAYS_ALLOW_WEB_PROXY_IPS environment variable

Add alwaysAllowWebProxyTargets function to parse comma-separated IPs from NEXAVPN_ALWAYS_ALLOW_WEB_PROXY_IPS environment variable with deduplication. Update mergeProfileAllowedIPs to accept webProxyTargets parameter and merge them into profile allowed IPs using /32 routes. Add WebProxyTargets field to wireguard.Peer struct and populate it in BuildSyncBundle and device enrollment/policy application

backend/internal/device/service.go

@@ -2,6 +2,7 @@ package device
 
 import (
 	"context"
+	"os"
 	"strings"
 
 	"github.com/google/uuid"
@@ -62,7 +63,7 @@ func (s *Service) Enroll(ctx context.Context, userID uuid.UUID, input EnrollRequ
 	if len(destinations) == 0 {
 		destinations = []string{"172.16.10.0/24"}
 	}
-	profileAllowedIPs := mergeProfileAllowedIPs(destinations, selectedGateway.DNSServers)
+	profileAllowedIPs := mergeProfileAllowedIPs(destinations, selectedGateway.DNSServers, alwaysAllowWebProxyTargets())
 
 	enrollment.Peer = PeerView{
 		AssignedIP: assignedIP,
@@ -184,13 +185,13 @@ func (s *Service) applyCurrentPolicy(ctx context.Context, enrollment EnrollmentR
 			Label: destination,
 		})
 	}
-	enrollment.Peer.AllowedIPs = mergeProfileAllowedIPs(destinations, enrollment.Peer.DNSServers)
+	enrollment.Peer.AllowedIPs = mergeProfileAllowedIPs(destinations, enrollment.Peer.DNSServers, alwaysAllowWebProxyTargets())
 	return withDebugProfile(enrollment), nil
 }
 
-func mergeProfileAllowedIPs(destinations []string, dnsServers []string) []string {
-	seen := make(map[string]struct{}, len(destinations)+len(dnsServers))
-	merged := make([]string, 0, len(destinations)+len(dnsServers))
+func mergeProfileAllowedIPs(destinations []string, dnsServers []string, webProxyTargets []string) []string {
+	seen := make(map[string]struct{}, len(destinations)+len(dnsServers)+len(webProxyTargets))
+	merged := make([]string, 0, len(destinations)+len(dnsServers)+len(webProxyTargets))
 
 	for _, destination := range destinations {
 		destination = strings.TrimSpace(destination)
@@ -216,6 +217,18 @@ func mergeProfileAllowedIPs(destinations []string, dnsServers []string) []string
 		merged = append(merged, route)
 	}
 
+	for _, target := range webProxyTargets {
+		route := dnsServerRoute(target)
+		if route == "" {
+			continue
+		}
+		if _, exists := seen[route]; exists {
+			continue
+		}
+		seen[route] = struct{}{}
+		merged = append(merged, route)
+	}
+
 	return merged
 }
 
@@ -229,3 +242,25 @@ func dnsServerRoute(value string) string {
 	}
 	return value + "/32"
 }
+
+func alwaysAllowWebProxyTargets() []string {
+	raw := os.Getenv("NEXAVPN_ALWAYS_ALLOW_WEB_PROXY_IPS")
+	if strings.TrimSpace(raw) == "" {
+		return nil
+	}
+
+	seen := make(map[string]struct{})
+	targets := make([]string, 0)
+	for _, part := range strings.Split(raw, ",") {
+		value := strings.TrimSpace(part)
+		if value == "" {
+			continue
+		}
+		if _, ok := seen[value]; ok {
+			continue
+		}
+		seen[value] = struct{}{}
+		targets = append(targets, value)
+	}
+	return targets
+}