Add shared type definitions and utility functions for timeline events

frontend/src/types/timeline.ts

+// 统一的时间轴事件类型定义
+export interface BaseTimelineEvent {
+  type: string;
+  title: string;
+  timestamp: number;
+  metadata?: Record<string, any>;
+}
+
+export interface ThoughtEvent extends BaseTimelineEvent {
+  content: string;
+  thinkingType?: string;
+}
+
+export interface ToolCallEvent extends BaseTimelineEvent {
+  toolName: string;
+  toolAction?: string;
+  toolInput?: any;
+  toolStatus: string;
+}
+
+export interface ToolResultEvent extends BaseTimelineEvent {
+  toolName: string;
+  toolAction?: string;
+  toolOutput?: any;
+  toolStatus: string;
+  executionTime?: number;
+}
+
+export interface ToolErrorEvent extends BaseTimelineEvent {
+  toolName: string;
+  errorMessage: string;
+  errorCode?: string;
+}
+
+export interface EmbedEvent extends BaseTimelineEvent {
+  embedUrl: string;
+  embedType?: string;
+  embedTitle: string;
+  embedHtmlContent?: string;
+}
+
+export type TimelineEvent = 
+  | ThoughtEvent 
+  | ToolCallEvent 
+  | ToolResultEvent 
+  | ToolErrorEvent 
+  | EmbedEvent 
+  | BaseTimelineEvent;
+
+// 事件类型标签映射
+export const eventTypeLabels: Record<string, string> = {
+  thought: '🧠 思考',
+  tool_call: '🔧 工具调用',
+  tool_result: '✅ 工具结果',
+  tool_error: '❌ 工具错误',
+  embed: '🌐 网页预览',
+  log: '📝 日志',
+  result: '🎯 最终答案',
+  observation: '🔍 观察'
+};
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frontend/src/utils/timelineUtils.ts

+// 时间轴工具函数库
+
+/**
+ * 检查是否为工具事件类型
+ * @param type 事件类型
+ * @returns 是否为工具事件类型
+ */
+export function isToolEventType(type: string): boolean {
+  return ['tool_call', 'tool_result', 'tool_error'].includes(type);
+}
+
+/**
+ * 检查工具输入是否有效
+ * @param event 事件对象
+ * @returns 工具输入是否有效
+ */
+export function hasValidToolInput(event: any): boolean {
+  return event.type === 'tool_call' && event.toolInput !== null && event.toolInput !== undefined;
+}
+
+/**
+ * 检查工具输出是否有效
+ * @param event 事件对象
+ * @returns 工具输出是否有效
+ */
+export function hasValidToolOutput(event: any): boolean {
+  return event.type === 'tool_result' && event.toolOutput !== null && event.toolOutput !== undefined;
+}
+
+/**
+ * 截断标题
+ * @param title 标题
+ * @param maxLength 最大长度
+ * @returns 截断后的标题
+ */
+export function truncateTitle(title: string, maxLength: number = 30): string {
+  if (!title) return '';
+  return title.length > maxLength ? title.substring(0, maxLength) + '...' : title;
+}
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frontend/src/utils/typeGuards.ts

+// 类型守卫函数
+
+import type { 
+  TimelineEvent, 
+  ThoughtEvent, 
+  ToolCallEvent, 
+  ToolResultEvent, 
+  ToolErrorEvent, 
+  EmbedEvent 
+} from '../types/timeline';
+
+/**
+ * 检查是否为思考事件
+ * @param event 事件对象
+ * @returns 是否为思考事件
+ */
+export function isThoughtEvent(event: TimelineEvent): event is ThoughtEvent {
+  return event.type === 'thought';
+}
+
+/**
+ * 检查是否为工具调用事件
+ * @param event 事件对象
+ * @returns 是否为工具调用事件
+ */
+export function isToolCallEvent(event: TimelineEvent): event is ToolCallEvent {
+  return event.type === 'tool_call';
+}
+
+/**
+ * 检查是否为工具结果事件
+ * @param event 事件对象
+ * @returns 是否为工具结果事件
+ */
+export function isToolResultEvent(event: TimelineEvent): event is ToolResultEvent {
+  return event.type === 'tool_result';
+}
+
+/**
+ * 检查是否为工具错误事件
+ * @param event 事件对象
+ * @returns 是否为工具错误事件
+ */
+export function isToolErrorEvent(event: TimelineEvent): event is ToolErrorEvent {
+  return event.type === 'tool_error';
+}
+
+/**
+ * 检查是否为嵌入事件
+ * @param event 事件对象
+ * @returns 是否为嵌入事件
+ */
+export function isEmbedEvent(event: TimelineEvent): event is EmbedEvent {
+  return event.type === 'embed';
+}
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