M5(T-M5-03): 高频出站节流——通用 Debouncer/Throttler + 网络变化防抖合并

- common 新增 Debouncer/Throttler 工具（不在桥核心按 handler 名节流，避免桥核心
  感知能力，违反零感知约束；由 Provider 自治应用）
- NetworkProvider：netAvailable/netLost/netCapabilitiesChange 三事件统一经 300ms
  防抖，切网瞬间多次突发合并为一次出站；onBackground/onDestroy 取消待发
- 说明：连续定位已受系统 timeInterval:5(5s) 约束、Device 为被动查询，无需额外节流；
  lzyzsd 协议 _handleMessageFromNative 单条语义，不做跨条合并（保 H5 零改动）

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

feature_capabilities/src/main/ets/providers/NetworkProvider.ets

@@ -8,7 +8,7 @@ import { connection } from '@kit.NetworkKit';
 import { BusinessError } from '@kit.BasicServicesKit';
 import { BridgeController } from 'feature_bridge';
 import { InboundHandlers, OutboundHandlers } from 'contracts';
-import { Logger } from 'common';
+import { Logger, Debouncer } from 'common';
 import { CapabilityContext, CapabilityProvider } from '../core/CapabilityProvider';
 
 /** 网络码（契约：1 无网 / 2 WiFi / 3 移动）。 */
@@ -16,11 +16,16 @@ const NET_NONE: string = '1';
 const NET_WIFI: string = '2';
 const NET_MOBILE: string = '3';
 
+/** 网络变化防抖窗口：切网瞬间 netAvailable/netCapabilitiesChange 常连发多次，合并为一次出站。 */
+const NET_DEBOUNCE_MS: number = 300;
+
 export class NetworkProvider implements CapabilityProvider {
   readonly name: string = 'network';
   private readonly log: Logger = Logger.tag('NetworkProvider');
   private bridge: BridgeController | undefined = undefined;
   private conn: connection.NetConnection | undefined = undefined;
+  /** T-M5-03：合并短时间内的多次网络变化，取最终状态后只出站一次。 */
+  private readonly debouncer: Debouncer = new Debouncer(NET_DEBOUNCE_MS);
 
   register(bridge: BridgeController, _ctx: CapabilityContext): void {
     this.bridge = bridge;
@@ -40,10 +45,12 @@ export class NetworkProvider implements CapabilityProvider {
 
   /** 槽去激活：注销网络变化订阅（非激活端不监听）。 */
   onBackground(): void {
+    this.debouncer.cancel();
     this.unsubscribe();
   }
 
   onDestroy(): void {
+    this.debouncer.cancel();
     this.unsubscribe();
   }
 
@@ -78,9 +85,10 @@ export class NetworkProvider implements CapabilityProvider {
     try {
       const conn: connection.NetConnection = connection.createNetConnection();
       this.conn = conn;
-      conn.on('netAvailable', () => this.broadcast());
-      conn.on('netLost', () => this.bridge?.callHandler(OutboundHandlers.GetNetwork, NET_NONE));
-      conn.on('netCapabilitiesChange', () => this.broadcast());
+      // 三类事件统一经防抖 → broadcast 计算最终网络码后出站一次（netLost 时 hasDefaultNet=false→NET_NONE）
+      conn.on('netAvailable', () => this.debouncer.run(() => this.broadcast()));
+      conn.on('netLost', () => this.debouncer.run(() => this.broadcast()));
+      conn.on('netCapabilitiesChange', () => this.debouncer.run(() => this.broadcast()));
       conn.register((e: BusinessError) => {
         if (e) {
           this.log.w(`net register failed: ${e.code} ${e.message}`);