refactor: data flow inversion, IPC contract fixes, and frontend adaptation

Data flow inversion:
- Add getHistoryForAgent() in conversations.ts — Agent now reads
  history directly from SQLite instead of receiving it from frontend
- Remove historyMessages parameter from agent:runStream IPC chain,
  add maxHistoryRounds for configurable context window
- Frontend (useAIChat.ts) pre-creates conversation before Agent call,
  removes history message collection logic

IPC fixes:
- Restore llm:chat and llm:chatStream handlers using pi-ai's
  completeSimple/streamSimple (P0-1: SQLLab compatibility)
- Send agent:complete with aborted flag in all abort paths to prevent
  hanging Promises in renderer (P0-2)
- Fix createConversation parameter order to match preload/data layer
  contract: (sessionId, title?) instead of (title, sessionId?) (P1)

Preload/frontend:
- Update preload API signatures and type declarations
- Use shared types for TokenUsage and AgentRuntimeStatus

electron/preload/apis/ai.ts

@@ -75,29 +75,9 @@ export interface ChatStreamChunk {
   finishReason?: 'stop' | 'length' | 'error'
 }
 
-// Agent API 类型
-export interface TokenUsage {
-  promptTokens: number
-  completionTokens: number
-  totalTokens: number
-}
-
-export interface AgentRuntimeStatus {
-  phase: 'preparing' | 'thinking' | 'tool_running' | 'responding' | 'completed' | 'aborted' | 'error'
-  round: number
-  toolsUsed: number
-  currentTool?: string
-  contextTokens: number
-  contextWindow: number
-  contextUsage: number
-  totalUsage: TokenUsage
-  nodeCount?: number
-  tagCount?: number
-  segmentSize?: number
-  checkoutCount?: number
-  activeAnchorNodeId?: string | null
-  updatedAt: number
-}
+// Agent API 类型 — 从 shared/types 统一导入
+export type { TokenUsage, AgentRuntimeStatus } from '../../shared/types'
+import type { TokenUsage, AgentRuntimeStatus } from '../../shared/types'
 
 export interface AgentStreamChunk {
   type: 'content' | 'think' | 'tool_start' | 'tool_result' | 'status' | 'done' | 'error'
@@ -651,28 +631,28 @@ export const llmApi = {
 export const agentApi = {
   /**
    * 执行 Agent 对话（流式）
-   * Agent 会自动调用工具获取数据并生成回答
-   * @param historyMessages 对话历史（可选，用于上下文关联）
+   * Agent 通过 context.conversationId 从后端 SQLite 读取对话历史
    * @param chatType 聊天类型（'group' | 'private'）
    * @param promptConfig 用户自定义提示词配置（可选）
    * @param locale 语言设置（可选，默认 'zh-CN'）
+   * @param maxHistoryRounds 最大历史轮数（可选，每轮 = user + assistant = 2 条）
    * @returns 返回 { requestId, promise }，requestId 可用于中止请求
    */
   runStream: (
     userMessage: string,
     context: ToolContext,
     onChunk?: (chunk: AgentStreamChunk) => void,
-    historyMessages?: Array<{ role: 'user' | 'assistant'; content: string }>,
     chatType?: 'group' | 'private',
     promptConfig?: PromptConfig,
-    locale?: string
+    locale?: string,
+    maxHistoryRounds?: number
   ): { requestId: string; promise: Promise<{ success: boolean; result?: AgentResult; error?: string }> } => {
     const requestId = `agent_${Date.now()}_${Math.random().toString(36).slice(2, 8)}`
     console.log(
       '[preload] Agent runStream 开始，requestId:',
       requestId,
-      'historyLength:',
-      historyMessages?.length ?? 0,
+      'conversationId:',
+      context.conversationId ?? 'none',
       'chatType:',
       chatType ?? 'group',
       'hasPromptConfig:',
@@ -713,9 +693,8 @@ export const agentApi = {
       ipcRenderer.on('agent:streamChunk', chunkHandler)
       ipcRenderer.on('agent:complete', completeHandler)
 
-      // 发起请求（传递历史消息、聊天类型、提示词配置和语言设置）
       ipcRenderer
-        .invoke('agent:runStream', requestId, userMessage, context, historyMessages, chatType, promptConfig, locale)
+        .invoke('agent:runStream', requestId, userMessage, context, chatType, promptConfig, locale, maxHistoryRounds)
         .then((result) => {
           console.log('[preload] Agent invoke 返回:', result)
           if (!result.success) {

electron/preload/index.d.ts

@@ -1,5 +1,6 @@
 import { ElectronAPI } from '@electron-toolkit/preload'
 import type { AnalysisSession, MessageType, ImportProgress, ExportProgress } from '../../src/types/base'
+import type { TokenUsage, AgentRuntimeStatus } from '../shared/types'
 import type {
   MemberActivity,
   MemberNameHistory,
@@ -582,29 +583,7 @@ interface RAGConfig {
   topK?: number
 }
 
-// Token 使用量类型
-interface TokenUsage {
-  promptTokens: number
-  completionTokens: number
-  totalTokens: number
-}
-
-interface AgentRuntimeStatus {
-  phase: 'preparing' | 'thinking' | 'tool_running' | 'responding' | 'completed' | 'aborted' | 'error'
-  round: number
-  toolsUsed: number
-  currentTool?: string
-  contextTokens: number
-  contextWindow: number
-  contextUsage: number
-  totalUsage: TokenUsage
-  nodeCount?: number
-  tagCount?: number
-  segmentSize?: number
-  checkoutCount?: number
-  activeAnchorNodeId?: string | null
-  updatedAt: number
-}
+// TokenUsage & AgentRuntimeStatus — imported from electron/shared/types.ts
 
 // Agent 相关类型
 interface AgentStreamChunk {
@@ -659,10 +638,10 @@ interface AgentApi {
     userMessage: string,
     context: ToolContext,
     onChunk?: (chunk: AgentStreamChunk) => void,
-    historyMessages?: Array<{ role: 'user' | 'assistant'; content: string }>,
     chatType?: 'group' | 'private',
     promptConfig?: PromptConfig,
-    locale?: string
+    locale?: string,
+    maxHistoryRounds?: number
   ) => { requestId: string; promise: Promise<{ success: boolean; result?: AgentResult; error?: string }> }
   abort: (requestId: string) => Promise<{ success: boolean; error?: string }>
 }