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>

pub/common/crypt/aesecb.go

@@ -0,0 +1,43 @@
+package crypt
+
+import (
+	"bytes"
+	"crypto/aes"
+)
+
+func PKCS7PaddingEx(ciphertext []byte, blockSize int) []byte {
+	padding := blockSize - len(ciphertext)%blockSize
+	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(ciphertext, padtext...)
+}
+
+func PKCS7UnPaddingEx(origData []byte) []byte {
+	length := len(origData)
+	unpadding := int(origData[length-1])
+	return origData[:(length - unpadding)]
+}
+
+func EcbDecrypt(data, key []byte) []byte {
+	block, _ := aes.NewCipher(key)
+	decrypted := make([]byte, len(data))
+	size := block.BlockSize()
+
+	for bs, be := 0, size; bs < len(data); bs, be = bs+size, be+size {
+		block.Decrypt(decrypted[bs:be], data[bs:be])
+	}
+
+	return PKCS7UnPaddingEx(decrypted)
+}
+
+func EcbEncrypt(data, key []byte) []byte {
+	block, _ := aes.NewCipher(key)
+	data = PKCS7PaddingEx(data, block.BlockSize())
+	decrypted := make([]byte, len(data))
+	size := block.BlockSize()
+
+	for bs, be := 0, size; bs < len(data); bs, be = bs+size, be+size {
+		block.Encrypt(decrypted[bs:be], data[bs:be])
+	}
+
+	return decrypted
+}