feat(api): 接入微信登录并原生实现咨询域（ECR-049/050）

小程序可在 Go 上完成微信手机号登录、测评、预约和下单，不再反代 Java。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/wechat/phone_test.go

@@ -0,0 +1,47 @@
+package wechat
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"testing"
+)
+
+func TestDecryptPhone(t *testing.T) {
+	key := make([]byte, 16)
+	iv := make([]byte, 16)
+	_, _ = rand.Read(key)
+	_, _ = rand.Read(iv)
+	plain := []byte(`{"phoneNumber":"13800138000","purePhoneNumber":"13800138000","watermark":{"appid":"wxapp"}}`)
+	padded := pkcs7Pad(plain, aes.BlockSize)
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+	enc := make([]byte, len(padded))
+	cipher.NewCBCEncrypter(block, iv).CryptBlocks(enc, padded)
+
+	phone, err := DecryptPhone(
+		base64.StdEncoding.EncodeToString(key),
+		base64.StdEncoding.EncodeToString(enc),
+		base64.StdEncoding.EncodeToString(iv),
+		"wxapp",
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if phone != "13800138000" {
+		t.Fatalf("got %s", phone)
+	}
+}
+
+func pkcs7Pad(b []byte, block int) []byte {
+	n := block - (len(b) % block)
+	out := make([]byte, len(b)+n)
+	copy(out, b)
+	for i := 0; i < n; i++ {
+		out[len(b)+i] = byte(n)
+	}
+	return out
+}