feat: 支持临时登录密码并完善 Emby 媒体详情兼容

- 新增 6 位临时密码生成与验证接口，支持 TV 及客户端快速登录
- 媒体及剧集详情补充 People 演职员信息解析与返回
- 优化剧集背景图与海报标签继承机制及播放时长兜底逻辑
- 增加临时密码登录相关的单元测试

internal/handler/auth.go

@@ -120,6 +120,25 @@ func changePasswordHandler(svc *service.Container) gin.HandlerFunc {
 			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
 			return
 		}
-		c.Status(http.StatusNoContent)
+			c.Status(http.StatusNoContent)
+		}
+	}
+
+func temporaryPasswordHandler(svc *service.Container) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		uid, ok := c.Get(middleware.CtxUserID)
+		if !ok || uid == nil {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
+			return
+		}
+		code, expireSec, err := svc.Auth.CreateTemporaryPassword(c.Request.Context(), uid.(string))
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+		c.JSON(http.StatusOK, gin.H{
+			"code":       code,
+			"expires_in": expireSec,
+		})
 	}
 }