feat: 16 funciones cybersecurity — análisis, crypto e IO de seguridad

12 funciones puras con implementación real:
HashSHA256, HashMD5, EntropyShannon, IsBase64, IsHex, ExtractURLs,
ParseIPCIDR, IPInRange, NormalizeURL, DetectSQLInjection,
LevenshteinDistance, JaccardSimilarity

4 funciones impuras con implementación real (stdlib):
LookupWhois, ResolveDNS, FetchHTTPHeaders, ScanPortTCP

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

functions/cybersecurity/normalize_url.go

@@ -0,0 +1,44 @@
+package cybersecurity
+
+import (
+	"net/url"
+	"strings"
+)
+
+// trackingParams lista de parametros de tracking comunes a eliminar.
+var trackingParams = map[string]bool{
+	"utm_source":   true,
+	"utm_medium":   true,
+	"utm_campaign": true,
+	"utm_term":     true,
+	"utm_content":  true,
+	"fbclid":       true,
+	"gclid":        true,
+	"ref":          true,
+	"mc_cid":       true,
+	"mc_eid":       true,
+}
+
+// NormalizeURL normaliza una URL: convierte el host a minusculas, elimina fragmentos
+// y remueve parametros de tracking comunes.
+func NormalizeURL(rawURL string) string {
+	u, err := url.Parse(rawURL)
+	if err != nil {
+		return rawURL
+	}
+
+	// Lowercase host
+	u.Host = strings.ToLower(u.Host)
+
+	// Eliminar fragmento
+	u.Fragment = ""
+
+	// Eliminar parametros de tracking
+	q := u.Query()
+	for param := range trackingParams {
+		q.Del(param)
+	}
+	u.RawQuery = q.Encode()
+
+	return u.String()
+}