refactor: 重构 token 管理，新增 NATS adapter 和多示例

按照 TOKEN_REFACTOR.md / FIX_CONFIG.md 方案重构核心层：
- miot: Init() 优先读 storage token，新增 RefreshAuthInfo() 和刷新回调
- xiaomi: Config 改用 AuthInfo 结构体（含 UUID/UID/DataDir/OnTokenRefreshed）
- xiaomi: NewClient(ctx, Config) 新签名，新增 RefreshToken()，后台自动刷新
- xiaomi/devices: 设备控制接口重构
- 新增示例 12_ac_subscribe，其余示例适配新 Config

xiaomi/devices/air_conditioner.go

@@ -2,6 +2,8 @@ package devices
 
 import (
 	"context"
+	"fmt"
+
 	"xiaomihome/xiaomi"
 )
 
@@ -130,21 +132,21 @@ type AirConditioner interface {
 	GetEco(ctx context.Context) (bool, error)
 
 	// 订阅
-	OnStateChanged(handler func(state ACState)) (string, error)
+	OnStateChanged(handler func(state ACState, changed string)) (string, error)
 }
 
-// ACState 空调完整状态
+// ACState 空调完整状态（字段名对齐 SPEC type）
 type ACState struct {
-	Power           bool      `json:"power"`
-	Mode            ACMode    `json:"mode"`
-	TargetTemp      float64   `json:"target_temp"`
-	CurrentTemp     float64   `json:"current_temp"`
-	TargetHumidity  int       `json:"target_humidity"`
-	CurrentHumidity int       `json:"current_humidity"`
-	FanSpeed        FanSpeed  `json:"fan_speed"`
-	Swing           SwingMode `json:"swing"`
-	AuxHeat         bool      `json:"aux_heat"`
-	Eco             bool      `json:"eco"`
+	On               bool      `json:"on"`                // SPEC: "on"
+	Mode             ACMode    `json:"mode"`              // SPEC: "mode"
+	TargetTemperature float64  `json:"targetTemperature"` // SPEC: "target-temperature"
+	Temperature      float64   `json:"temperature"`       // SPEC: "temperature" (当前温度)
+	TargetHumidity   int       `json:"targetHumidity"`    // SPEC: "target-humidity"
+	CurrentHumidity  int       `json:"currentHumidity"`   // SPEC: "relative-humidity"
+	FanLevel         FanSpeed  `json:"fanLevel"`          // SPEC: "fan-level"
+	Swing            SwingMode `json:"swing"`             // SPEC: "swing"
+	AuxHeat          bool      `json:"auxHeat"`           // SPEC: "heater"
+	Eco              bool      `json:"eco"`               // SPEC: "eco"
 }
 
 type acDevice struct {
@@ -159,6 +161,8 @@ type acDevice struct {
 	propCurrentHumidity siidPiid // "relative-humidity"
 	propAuxHeat         siidPiid // "aux-heat" or "heater"
 	propEco             siidPiid // "eco"
+
+	stateCache ACState // MQTT 推送维护的本地缓存
 }
 
 // NewAirConditioner creates an AirConditioner control for the given device.
@@ -430,19 +434,58 @@ func (d *acDevice) GetEco(ctx context.Context) (bool, error) {
 	return false, nil
 }
 
-func (d *acDevice) OnStateChanged(handler func(state ACState)) (string, error) {
-	if !d.propOn.valid {
+// propField maps a SPEC short name to a siid/piid pair and a cache-update function.
+type propField struct {
+	siid, piid int
+	name       string
+	fill       func(*ACState, interface{})
+}
+
+func (d *acDevice) OnStateChanged(handler func(state ACState, changed string)) (string, error) {
+	fields := d.propFields()
+	if len(fields) == 0 {
 		return "", xiaomi.ErrNotSupported
 	}
-	return d.SubProp(d.propOn.siid, 0, func(did string, prop *xiaomi.PropertyValue) {
-		state := ACState{}
-		if b, ok := prop.Value.(bool); ok {
-			state.Power = b
+	return d.SubProp(0, 0, func(did string, prop *xiaomi.PropertyValue) {
+		for _, f := range fields {
+			if f.siid == prop.SIID && f.piid == prop.PIID {
+				f.fill(&d.stateCache, prop.Value)
+				handler(d.stateCache, f.name)
+				return
+			}
 		}
-		handler(state)
 	})
 }
 
+func (d *acDevice) propFields() []propField {
+	var fields []propField
+	add := func(sp siidPiid, name string, fill func(*ACState, interface{})) {
+		if sp.valid {
+			fields = append(fields, propField{sp.siid, sp.piid, name, fill})
+		}
+	}
+	add(d.propOn, "on", func(s *ACState, v interface{}) { s.On, _ = v.(bool) })
+	add(d.propMode, "mode", func(s *ACState, v interface{}) {
+		switch m := v.(type) {
+		case string: s.Mode = ACMode(m)
+		case float64: s.Mode = ACMode(fmt.Sprintf("%.0f", m))
+		}
+	})
+	add(d.propTargetTemp, "target-temperature", func(s *ACState, v interface{}) { s.TargetTemperature = toFloat(v) })
+	add(d.propCurrentTemp, "temperature", func(s *ACState, v interface{}) { s.Temperature = toFloat(v) })
+	add(d.propFanSpeed, "fan-level", func(s *ACState, v interface{}) {
+		if v, ok := v.(float64); ok { s.FanLevel = FanSpeed(fmt.Sprintf("%.0f", v)) }
+	})
+	add(d.propSwing, "swing", func(s *ACState, v interface{}) {
+		if v, ok := v.(float64); ok { s.Swing = SwingMode(fmt.Sprintf("%.0f", v)) }
+	})
+	add(d.propTargetHumidity, "target-humidity", func(s *ACState, v interface{}) { s.TargetHumidity = int(toFloat(v)) })
+	add(d.propCurrentHumidity, "relative-humidity", func(s *ACState, v interface{}) { s.CurrentHumidity = int(toFloat(v)) })
+	add(d.propAuxHeat, "heater", func(s *ACState, v interface{}) { s.AuxHeat, _ = v.(bool) })
+	add(d.propEco, "eco", func(s *ACState, v interface{}) { s.Eco, _ = v.(bool) })
+	return fields
+}
+
 // toFloat converts an interface{} to float64.
 func toFloat(v interface{}) float64 {
 	switch n := v.(type) {