refactor: simplified and used db.go for operations on whitelists

auth.go

@@ -151,7 +151,6 @@ func logsHandler(cfg Config, db *sql.DB) http.HandlerFunc {
 	}
 }
 
-// --- Perm whitelist API endpoints (optional but useful) ---
 func permWhitelistAddHandler(cfg Config, db *sql.DB) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if !verifyAPIKey(r, cfg.APIToken) {
@@ -159,7 +158,7 @@ func permWhitelistAddHandler(cfg Config, db *sql.DB) http.HandlerFunc {
 			return
 		}
 		type request struct {
-			Entry string `json:"entry"` // IP or CIDR
+			Entry string `json:"entry"`
 		}
 		var req request
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
@@ -204,7 +203,6 @@ func permWhitelistDeleteHandler(cfg Config, db *sql.DB) http.HandlerFunc {
 	}
 }
 
-// Helper to get real client IP for audit (X-Real-IP or remote addr)
 func getClientIP(r *http.Request) string {
 	if ip := r.Header.Get("X-Real-IP"); ip != "" {
 		return ip