feat: 从黄果 NET hgdjnet-server 9bfbafe 导入 HKDJ 官网后端

来源：hgdjnet-server 9bfbafe10d417deea959bd53117bc88a10e60a83
项目身份 HKDJ / JHA-216，独立官网仓库，Jenkins 守卫键 hkdjnet
测试目录 /server/hkdj_net，App/Web API 30331/30332

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

web/middleware/api_security/genkey.go

@@ -0,0 +1,25 @@
+package api_security
+
+import (
+	"crypto/sha256"
+	"math/rand"
+)
+
+func GenerateKey(secret string) []byte {
+	key := sha256.Sum256([]byte(secret))
+	return key[:]
+}
+
+func GenerateIV(secret, salt string) []byte {
+	return GenerateKey(secret + salt)[:16]
+}
+
+const strPool = "012345679qwertyuioplkjhgfdsazxcvbnmQWERTYUIOPLKJHGFDSAZXCVBNM"
+
+func GenerateIVSalt() string {
+	var n [16]byte
+	for i := 0; i < 16; i++ {
+		n[i] = byte(strPool[rand.Intn(len(strPool))])
+	}
+	return string(n[:])
+}