feat(miniprogram): add intracity delivery service APIs

[Lumiaqian]

Summary

Add WeChat intracity (same-city) delivery service APIs for miniprogram.

Official Documentation: https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/industry/express/business/intracity_service.html

New APIs

Store Management

• IntracityApply - 开通门店权限
• IntracityCreateStore - 创建门店
• IntracityQueryStore - 查询门店
• IntracityUpdateStore - 更新门店

Payment & Balance

• IntracityStoreCharge - 门店运费充值
• IntracityStoreRefund - 门店运费退款
• IntracityQueryFlow - 门店运费流水查询
• IntracityBalanceQuery - 门店余额查询

Order Management

• IntracityPreAddOrder - 预下配送单（查询运费）
• IntracityAddOrder - 创建配送单
• IntracityQueryOrder - 查询配送单
• IntracityCancelOrder - 取消配送单
• IntracityMockNotify - 模拟配送回调（仅用于测试）

Usage Example

miniprogram := wc.GetMiniProgram(cfg)
intracity := miniprogram.GetIntracity()

// Create store
res, err := intracity.IntracityCreateStore(ctx, &express.CreateStoreRequest{
    OutStoreID: "store001",
    StoreName:  "Test Store",
    AddressInfo: express.IntracityAddressInfo{
        Province: "广东省",
        City:     "深圳市",
        Area:     "南山区",
        House:    "深南大道10000号",
        Lat:      22.540366,
        Lng:      113.934559,
        Phone:    "13800001380",
    },
})

// Create delivery order
orderRes, err := intracity.IntracityAddOrder(ctx, &express.AddOrderRequest{
    WxStoreID:   res.WxStoreID,
    OutOrderID:  "order001",
    UserOpenID:  "user_openid",
    UserPhone:   "13900001390",
    UserName:    "张三",
    UserLat:     22.550000,
    UserLng:     113.940000,
    UserAddress: "深圳市南山区xxx路xxx号",
})

Checklist

• Code follows existing patterns in this repository
• go fmt and go vet pass
• go build ./... succeeds

[houseme]

LGTM

[Copilot]

Pull request overview

This pull request adds comprehensive WeChat intracity (same-city) delivery service APIs to the miniprogram package. The implementation provides a complete set of endpoints for managing stores, payments, balances, and delivery orders for same-city delivery services.

Changes:

• Added GetIntracity() method to MiniProgram struct for accessing intracity delivery APIs
• Implemented 12 new API methods covering store management, payment/balance operations, and order lifecycle
• Defined comprehensive type definitions and request/response structures following WeChat's official API specifications

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
miniprogram/miniprogram.go	Added GetIntracity() accessor method returning Express instance for intracity delivery APIs
miniprogram/express/intracity.go	Complete implementation of 12 intracity delivery API methods with supporting types, constants, and data structures

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