feat: SafeLine CE 9.3.9 with pro features

- Remove telemetry: disabled all phone-home (installation notify, false positives, behavior tracking, upgrade tips)
- Version branding: removed 'ce-' prefix, product name changed to '长亭雷池 WAF'
- Detection engine enhancement: strict preset enables all 17 modules with aggressive configs
- Multi-user RBAC: admin/operator/viewer roles with password + TOTP 2FA
- Rate limiting: nginx limit_req per website (RPS, burst, action)
- JS Challenge: browser fingerprint verification page with cookie-based bypass
- Security fixes: removed InsecureSkipVerify, hardcoded credentials, NO_AUTH backdoor

management/tcontrollerd/utils/random.go

@@ -0,0 +1,18 @@
+package utils
+
+import (
+	"math/rand"
+	"time"
+)
+
+var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+
+func RandStr(n int) string {
+	rand.Seed(time.Now().UnixNano())
+
+	b := make([]rune, n)
+	for i := range b {
+		b[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(b)
+}