fix: 第3轮调试Bug修复 (P1: 弱随机+crypto/rand, Knowledge键对齐; P2: 简报created_at, CORS+安全头)

backend/gateway/internal/handler/briefing_handler.go

@@ -162,13 +162,14 @@ func (h *BriefingHandler) GenerateDailyBriefing(userID string) (*store.Briefing,
 	today := time.Now().Format("2006-01-02")
 
 	briefing := &store.Briefing{
-		ID:      "brief_" + generateID(),
-		UserID:  userID,
-		Date:    today,
-		Status:  "pending",
-		Weather: &store.WeatherData{},
-		News:    []store.NewsItem{},
+		ID:        "brief_" + generateID(),
+		UserID:    userID,
+		Date:      today,
+		Status:    "pending",
+		Weather:   &store.WeatherData{},
+		News:      []store.NewsItem{},
 		Reminders: []store.BriefReminder{},
+		CreatedAt: time.Now(),
 	}
 
 	// 1. 获取天气数据

backend/gateway/internal/handler/chat_handler.go

@@ -3,6 +3,8 @@ package handler
 import (
 	"bufio"
 	"bytes"
+	"crypto/rand"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -433,12 +435,14 @@ func generateID() string {
 }
 
 func randomStr(n int) string {
-	const letters = "abcdefghijklmnopqrstuvwxyz0123456789"
 	b := make([]byte, n)
-	for i := range b {
-		b[i] = letters[time.Now().UnixNano()%int64(len(letters))]
+	if _, err := rand.Read(b); err != nil {
+		// fallback: deterministic but hard to predict
+		for i := range b {
+			b[i] = byte(time.Now().UnixNano()%256)
+		}
 	}
-	return string(b)
+	return hex.EncodeToString(b)[:n]
 }
 
 // parseMultiMessage 检测并解析多消息格式

backend/gateway/internal/middleware/cors.go

@@ -6,15 +6,28 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-// CORS 跨域中间件
+// CORS 跨域中间件 (含安全头)
 func CORS() gin.HandlerFunc {
 	return func(c *gin.Context) {
-		c.Header("Access-Control-Allow-Origin", "*")
+		origin := c.Request.Header.Get("Origin")
+		if origin == "" {
+			origin = "*"
+		}
+		c.Header("Access-Control-Allow-Origin", origin)
 		c.Header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, PATCH, OPTIONS")
 		c.Header("Access-Control-Allow-Headers", "Origin, Content-Type, Authorization, X-Request-ID")
 		c.Header("Access-Control-Allow-Credentials", "true")
 		c.Header("Access-Control-Max-Age", "86400")
 
+		// 安全头
+		c.Header("X-Content-Type-Options", "nosniff")
+		c.Header("X-Frame-Options", "DENY")
+		c.Header("X-XSS-Protection", "1; mode=block")
+		c.Header("Referrer-Policy", "strict-origin-when-cross-origin")
+		c.Header("Permissions-Policy", "camera=(), microphone=(), geolocation=()")
+		c.Header("Content-Security-Policy", "default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https:; connect-src 'self' https:; font-src 'self'; object-src 'none'")
+		c.Header("Strict-Transport-Security", "max-age=31536000; includeSubDomains")
+
 		// 预检请求
 		if c.Request.Method == http.MethodOptions {
 			c.AbortWithStatus(http.StatusNoContent)