feat(支付): 新增Apple IAP支付支持

实现Apple应用内购支付功能，包括：
1. 新增AppleIAP和ApplePay支付平台枚举
2. 添加IAP验证接口/v1/public/iap/verify处理初购验证
3. 实现Apple服务器通知处理逻辑/v1/iap/notifications
4. 新增JWS验签和JWKS公钥缓存功能
5. 复用现有订单系统处理IAP支付订单

相关文档已更新，包含接入方案和实现细节

pkg/payment/platform.go

@@ -10,6 +10,8 @@ const (
 	EPay
 	Balance
 	CryptoSaaS
+	AppleIAP
+	ApplePay
 	UNSUPPORTED Platform = -1
 )
 
@@ -19,6 +21,8 @@ var platformNames = map[string]Platform{
 	"AlipayF2F":   AlipayF2F,
 	"EPay":        EPay,
 	"balance":     Balance,
+	"AppleIAP":    AppleIAP,
+	"ApplePay":    ApplePay,
 	"unsupported": UNSUPPORTED,
 }
 
@@ -80,5 +84,24 @@ func GetSupportedPlatforms() []types.PlatformInfo {
 				"secret_key": "Secret Key",
 			},
 		},
+		{
+			Platform:    AppleIAP.String(),
+			PlatformUrl: "https://developer.apple.com/help/app-store-connect/",
+			PlatformFieldDescription: map[string]string{
+				"issuer_id":   "App Store Connect Issuer ID",
+				"key_id":      "App Store Connect Key ID",
+				"private_key": "Private Key (ES256)",
+				"environment": "Environment: Sandbox/Production",
+			},
+		},
+		{
+			Platform:    ApplePay.String(),
+			PlatformUrl: "https://stripe.com",
+			PlatformFieldDescription: map[string]string{
+				"public_key":     "Publishable key",
+				"secret_key":     "Secret key",
+				"webhook_secret": "Webhook secret",
+			},
+		},
 	}
 }