feat(PostHog): 添加双写模式支持自托管 + Cloud 并行

- .env.production: 主实例改为自托管 101.43.133.214:7050
- .env.production: 添加 Cloud 双写配置（DUAL_WRITE=true）
- posthog.js: initPostHog() 支持初始化 Cloud 第二实例
- posthog.js: trackEvent() 事件同时发送到两个实例
- posthog.js: identifyUser() 用户身份同步到两个实例
- posthog.js: resetUser() 退出时重置两个实例

目的：验证自托管数据采集有效性 + Cloud 作为兜底策略

⚠️ 部署前需将 REACT_APP_POSTHOG_CLOUD_KEY 替换为真实 Key

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.env.production

@@ -20,11 +20,16 @@ REACT_APP_API_URL=https://api.valuefrontier.cn
 # PostHog 分析配置（生产环境）
 # PostHog API Key（从 PostHog 项目设置中获取）
 REACT_APP_POSTHOG_KEY=phc_xKlRyG69Bx7hgOdFeCeLUvQWvSjw18ZKFgCwCeYezWF
-# PostHog API Host（使用 PostHog Cloud）
+# PostHog API Host（自托管实例）
-REACT_APP_POSTHOG_HOST=https://app.posthog.com
+REACT_APP_POSTHOG_HOST=http://101.43.133.214:7050
 # 启用会话录制（Session Recording）用于回放用户操作、排查问题
 REACT_APP_ENABLE_SESSION_RECORDING=true
 
+# PostHog Cloud 双写配置（验证自托管有效性 + Cloud 兜底）
+REACT_APP_POSTHOG_CLOUD_KEY=phc_xxxxxxx
+REACT_APP_POSTHOG_CLOUD_HOST=https://us.posthog.com
+REACT_APP_POSTHOG_DUAL_WRITE=true
+
 # React 构建优化配置
 # 禁用 source map 生成（生产环境不需要，提升打包速度和安全性）
 GENERATE_SOURCEMAP=false

src/lib/posthog.js

@@ -8,6 +8,7 @@ let isInitialized = false;
 /**
  * Initialize PostHog SDK
  * Should be called once when the app starts
+ * 支持双写模式：同时发送到自托管和 Cloud
  */
 export const initPostHog = () => {
   // 开发环境禁用 PostHog（减少日志噪音，仅生产环境启用）
@@ -26,6 +27,7 @@ export const initPostHog = () => {
 
   const apiKey = process.env.REACT_APP_POSTHOG_KEY;
   const apiHost = process.env.REACT_APP_POSTHOG_HOST || 'https://app.posthog.com';
+  const dualWrite = process.env.REACT_APP_POSTHOG_DUAL_WRITE === 'true';
 
   if (!apiKey) {
     console.warn('⚠️ PostHog API key not found. Analytics will be disabled.');
@@ -35,6 +37,7 @@ export const initPostHog = () => {
   isInitializing = true;
 
   try {
+    // 主实例（自托管）
     posthog.init(apiKey, {
       api_host: apiHost,
 
@@ -94,6 +97,26 @@ export const initPostHog = () => {
       },
     });
 
+    // Cloud 实例（双写备份）
+    if (dualWrite) {
+      const cloudKey = process.env.REACT_APP_POSTHOG_CLOUD_KEY;
+      const cloudHost = process.env.REACT_APP_POSTHOG_CLOUD_HOST || 'https://us.posthog.com';
+
+      if (cloudKey && cloudKey !== 'phc_xxxxxxx') {
+        posthog.init(cloudKey, {
+          api_host: cloudHost,
+          capture_pageview: true,
+          capture_pageleave: true,
+          autocapture: true,
+          session_recording: { enabled: false }, // Cloud 不需要录屏，节省流量
+        }, 'cloud'); // 第三个参数是实例名称
+
+        console.log('[PostHog] 双写模式已启用：自托管 + Cloud');
+      } else {
+        console.warn('[PostHog] 双写模式已启用但 Cloud API Key 未配置');
+      }
+    }
+
     isInitialized = true;
   } catch (error) {
     // 忽略 AbortError（通常由热重载或快速导航引起）
@@ -116,6 +139,7 @@ export const getPostHog = () => {
 /**
  * Identify user with PostHog
  * Call this after successful login/registration
+ * 双写模式下同时同步到 Cloud
  *
  * @param {string} userId - Unique user identifier
  * @param {object} userProperties - User properties (email, name, subscription_tier, etc.)
@@ -126,8 +150,7 @@ export const identifyUser = (userId, userProperties = {}) => {
     return;
   }
 
-  try {
+  const properties = {
-    posthog.identify(userId, {
     email: userProperties.email,
     username: userProperties.username,
     subscription_tier: userProperties.subscription_tier || 'free',
@@ -135,7 +158,23 @@ export const identifyUser = (userId, userProperties = {}) => {
     registration_date: userProperties.registration_date,
     last_login: new Date().toISOString(),
     ...userProperties,
-    });
+  };
+
+  try {
+    // 主实例
+    posthog.identify(userId, properties);
+
+    // 双写到 Cloud
+    if (process.env.REACT_APP_POSTHOG_DUAL_WRITE === 'true') {
+      try {
+        const cloudInstance = posthog.getInstance('cloud');
+        if (cloudInstance) {
+          cloudInstance.identify(userId, properties);
+        }
+      } catch (e) {
+        // 静默失败，不影响主流程
+      }
+    }
   } catch (error) {
     console.error('❌ User identification failed:', error);
   }
@@ -157,16 +196,32 @@ export const setUserProperties = (properties) => {
 
 /**
  * Track custom event
+ * 双写模式下同时发送到 Cloud
  *
  * @param {string} eventName - Name of the event
  * @param {object} properties - Event properties
  */
 export const trackEvent = (eventName, properties = {}) => {
-  try {
+  const eventProperties = {
-    posthog.capture(eventName, {
     ...properties,
     timestamp: new Date().toISOString(),
-    });
+  };
+
+  try {
+    // 主实例
+    posthog.capture(eventName, eventProperties);
+
+    // 双写到 Cloud
+    if (process.env.REACT_APP_POSTHOG_DUAL_WRITE === 'true') {
+      try {
+        const cloudInstance = posthog.getInstance('cloud');
+        if (cloudInstance) {
+          cloudInstance.capture(eventName, eventProperties);
+        }
+      } catch (e) {
+        // 静默失败，不影响主流程
+      }
+    }
   } catch (error) {
     console.error('❌ Event tracking failed:', error);
   }
@@ -220,10 +275,24 @@ export const trackPageView = (pagePath, properties = {}) => {
 /**
  * Reset user session
  * Call this on logout
+ * 双写模式下同时重置 Cloud 实例
  */
 export const resetUser = () => {
   try {
+    // 主实例
     posthog.reset();
+
+    // 双写：重置 Cloud 实例
+    if (process.env.REACT_APP_POSTHOG_DUAL_WRITE === 'true') {
+      try {
+        const cloudInstance = posthog.getInstance('cloud');
+        if (cloudInstance) {
+          cloudInstance.reset();
+        }
+      } catch (e) {
+        // 静默失败
+      }
+    }
   } catch (error) {
     console.error('❌ Session reset failed:', error);
   }