chore: 提交高层 xiaomi 封装库及示例

- 新增 xiaomi/examples/ 下 8 个示例程序（用户/家庭查询、设备列表、开关/灯光/空调控制、属性订阅、高级过滤分类、SPEC 解析）
- miot_client_sub.go: 重构 SubProp/SubEvent，使用 buildPropTopic/buildEventTopic 支持通配符订阅（siid/piid=0 → +），并修复锁顺序问题（将 RequestRefreshProp 移到 Lock 外）
- spec_parser.go: 新增 downloadSpecFile 方法，本地 SPEC 文件缺失时自动从 miot-spec.org 下载
- ARCH_PLAN.md: 架构设计从 Proposed 更新为 Accepted（v1.0→v1.1），补充设备分类/工厂/SPEC 映射等模块设计
- xiaomi/: 新增 miot 上层强类型封装模块，包含 Client 主入口、用户/家庭/设备 API、属性读写、动作调用、订阅通知，以及 devices/ 设备控制抽象（Switch/Light/AirConditioner/Fan/Cover/Humidifier/Vacuum/WaterHeater/Thermostat）和 specs/ SPEC 查询辅助
- 更多 xiaomi 示例（风扇/窗帘/传感器控制）

xiaomi/examples/03_switch_control/data/cert/mihome_ca.cert

@@ -0,0 +1,21 @@
+-----BEGIN CERTIFICATE-----
+MIIBazCCAQ+gAwIBAgIEA/UKYDAMBggqhkjOPQQDAgUAMCIxEzARBgNVBAoTCk1p
+amlhIFJvb3QxCzAJBgNVBAYTAkNOMCAXDTE2MTEyMzAxMzk0NVoYDzIwNjYxMTEx
+MDEzOTQ1WjAiMRMwEQYDVQQKEwpNaWppYSBSb290MQswCQYDVQQGEwJDTjBZMBMG
+ByqGSM49AgEGCCqGSM49AwEHA0IABL71iwLa4//4VBqgRI+6xE23xpovqPCxtv96
+2VHbZij61/Ag6jmi7oZ/3Xg/3C+whglcwoUEE6KALGJ9vccV9PmjLzAtMAwGA1Ud
+EwQFMAMBAf8wHQYDVR0OBBYEFJa3onw5sblmM6n40QmyAGDI5sURMAwGCCqGSM49
+BAMCBQADSAAwRQIgchciK9h6tZmfrP8Ka6KziQ4Lv3hKfrHtAZXMHPda4IYCIQCG
+az93ggFcbrG9u2wixjx1HKW4DUA5NXZG0wWQTpJTbQ==
+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

xiaomi/examples/03_switch_control/main.go

@@ -0,0 +1,95 @@
+// Package main demonstrates switch device control.
+// 运行前提：已配置环境变量 XIAOMI_CLIENT_ID / XIAOMI_CLIENT_SECRET / XIAOMI_ACCESS_TOKEN。
+package main
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"xiaomihome/xiaomi"
+	"xiaomihome/xiaomi/devices"
+	miotconfig "xiaomihome/miot/examples/config"
+)
+
+func main() {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	cfg, err := miotconfig.LoadConfig("../../../miot/examples/config.json")
+	if err != nil {
+		log.Fatal("请先运行 miot/examples/cloud_oauth 获取 token:", err)
+	}
+
+	client, err := xiaomi.NewClient(ctx, xiaomi.Config{
+		ClientSecret: "",
+		AccessToken:  cfg.AuthInfo.AccessToken,
+		UID:          cfg.UID,
+		UUID:         cfg.UUID,
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer client.Close()
+
+	const targetDID = "2170429382"
+
+	info, err := client.GetDevice(ctx, targetDID)
+	if err != nil {
+		log.Fatalf("获取设备 %s 失败: %v", targetDID, err)
+	}
+
+	sw, err := devices.NewSwitch(client, info)
+	if err != nil {
+		log.Fatalf("创建 Switch 失败: %v", err)
+	}
+
+	log.Printf("开关: %s (DID: %s, 型号: %s)", info.Name, info.DID, info.Model)
+
+	log.Printf("通道数: %d", sw.ChannelCount())
+
+	if sw.ChannelCount() == 1 {
+		demoSingleChannel(ctx, sw)
+	} else {
+		demoMultiChannel(ctx, sw)
+	}
+
+	log.Println("开关控制演示完毕")
+}
+
+func demoSingleChannel(ctx context.Context, sw devices.Switch) {
+	on, _ := sw.IsOn(ctx)
+	log.Printf("当前状态: on=%v", on)
+
+	log.Println("执行 Toggle...")
+	sw.Toggle(ctx)
+	time.Sleep(1 * time.Second)
+	newOn, _ := sw.IsOn(ctx)
+	log.Printf("Toggle 后: on=%v", newOn)
+}
+
+func demoMultiChannel(ctx context.Context, sw devices.Switch) {
+	for ch := 1; ch <= sw.ChannelCount(); ch++ {
+		on, err := sw.IsChannelOn(ctx, ch)
+		if err != nil {
+			log.Printf("通道 %d: 查询失败 %v", ch, err)
+			continue
+		}
+		log.Printf("通道 %d: on=%v", ch, on)
+
+		log.Printf("  通道 %d 执行 Toggle...", ch)
+		sw.ToggleChannel(ctx, ch)
+		time.Sleep(1 * time.Second)
+		newOn, _ := sw.IsChannelOn(ctx, ch)
+		log.Printf("  通道 %d Toggle 后: on=%v", ch, newOn)
+
+		// 恢复原状态
+		if on {
+			log.Printf("  通道 %d 恢复为 开", ch)
+			sw.TurnOnChannel(ctx, ch)
+		} else {
+			log.Printf("  通道 %d 恢复为 关", ch)
+			sw.TurnOffChannel(ctx, ch)
+		}
+	}
+}