feat: 模型推理异步加载与对话链路修复，同步基线

模型推理全异步化改造：
- 计算节点 InferenceSession 改为后台线程异步加载模型，load 立即返回，
  加载期间事件循环保持响应（/inference/status 与 /health 不阻塞）
- 后端模型加载改为异步派发 + 轮询对账器（reconcile_inference_loads），
  任务状态由 starting 自动推进到 ready/error，解决多节点启动超时
  （timeout of 120000ms exceeded）
- 推理删除/卸载改为任务感知 + 短超时，删除先删记录再 best-effort 卸载，
  不再被不可达节点阻塞；同节点新模型替换旧任务标记失效
- 流式对话透传 task_id/node_id 路由到真正加载模型的算力节点，
  useStreamChat 解析 SSE 错误帧以干净文案展示
- 对话历史按任务 id 本地持久化，退出重进可恢复；移除页脚提示文本
- 新增后端推理异步加载与计算节点异步状态机单元测试

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

frontend/src/api/modules/compare.ts

@@ -1,6 +1,8 @@
 import { get, post, del } from '../request'
 import type { CompareTask, CompareModelRef } from '@/types'
 
+const INFERENCE_START_TIMEOUT_MS = 15 * 60 * 1000
+
 /** 推理/对比任务列表 */
 export const getCompareList = () => get<CompareTask[]>('/model-compare')
 
@@ -12,7 +14,7 @@ export const createCompare = (data: Partial<CompareTask>) =>
   post<{ id: string | number }>('/model-compare', data)
 
 /** 删除任务 */
-export const deleteCompare = (id: string | number) => del(`/model-compare/${id}`)
+export const deleteCompare = (id: string | number) => del(`/model-compare/${id}`, undefined, { timeout: 60_000 })
 
 /** 更新任务加载状态 */
 export const updateLoadStatus = (id: string | number, load_status: any) =>
@@ -34,7 +36,8 @@ export const stopModelByPid = (pid: number) =>
   post('/model-compare/stop-by-pid', { pid })
 
 /** 加载任务 */
-export const loadCompare = (id: string | number) => post(`/model-compare/${id}/load`)
+export const loadCompare = (id: string | number) =>
+  post(`/model-compare/${id}/load`, undefined, { timeout: INFERENCE_START_TIMEOUT_MS })
 
 /** 卸载任务 */
 export const unloadCompare = (id: string | number) => post(`/model-compare/${id}/unload`)
@@ -81,6 +84,10 @@ export const streamChatReal = (data: any): Promise<Response> => {
       temperature: data.temperature ?? 0.7,
       top_p: data.top_p ?? 0.95,
       max_tokens: data.max_tokens ?? 2048,
+      // 透传 task_id/node_id，让后端按 load_status 路由到真正加载了模型的算力节点，
+      // 避免在多节点时回退到“第一个在线节点”导致连接失败
+      task_id: data.task_id,
+      node_id: data.node_id,
     }),
   })
 }
@@ -94,8 +101,8 @@ export const batchChat = (data: any) => post('/model-chat/batch', data)
 /** 本地 transformers 模型对话 */
 export const localChat = (data: any) => post('/model-chat/local/chat', data)
 
-/** 预加载本地模型（模型加载耗时长，超时 5 分钟） */
-export const preloadLocalModel = (data: any) => post('/model-chat/local/preload', data, { timeout: 300000 })
+/** 预加载本地模型（模型加载耗时长，超时 15 分钟） */
+export const preloadLocalModel = (data: any) => post('/model-chat/local/preload', data, { timeout: INFERENCE_START_TIMEOUT_MS })
 
-/** 预加载已训练模型（超时 5 分钟） */
-export const preloadTrainedModel = (data: any) => post('/model-chat/trained/preload', data, { timeout: 300000 })
+/** 预加载已训练模型（超时 15 分钟） */
+export const preloadTrainedModel = (data: any) => post('/model-chat/trained/preload', data, { timeout: INFERENCE_START_TIMEOUT_MS })

frontend/src/api/modules/fineTune.ts

@@ -1,6 +1,16 @@
 import { get, post, put, del } from '../request'
 import type { FineTuneStartPayload, FineTuneTask, TrainingProgress, LogContent } from '@/types'
 
+export interface FineTuneMetricPoint {
+  step: number
+  epoch?: number | null
+  loss?: number | null
+  grad_norm?: number | null
+  learning_rate?: number | null
+  raw?: string
+  create_time?: string
+}
+
 export interface TrainingDiagnostic {
   level: string
   title: string
@@ -80,6 +90,10 @@ export const getFineTuneLogs = (
   params: { tail_lines?: number; offset?: number; limit?: number } = {},
 ) => get<LogContent & { job_id?: string; source?: string }>(`/fine-tune/${id}/logs`, params)
 
+/** 获取训练指标曲线数据 */
+export const getFineTuneMetrics = (id: string | number) =>
+  get<FineTuneMetricPoint[]>(`/fine-tune/${id}/metrics`)
+
 /** 启动 TensorBoard */
 export const startTensorboard = () => post('/fine-tune/tensorboard/start')
 

frontend/src/api/modules/model.ts

@@ -88,10 +88,14 @@ export const updateModelPurpose = (id: string | number, purpose: string) =>
 
 /** 合并 LoRA 权重 */
 export const mergeModel = (data: {
+  trained_model_id?: string | number
   model_name: string
   train_method: string
   base_model_path: string
-}) => post('/model-manage/merge', data)
+  adapter_path?: string
+  compute_node_id?: string
+  output_model_name?: string
+}) => post('/model-manage/merge', data, { timeout: 15 * 60 * 1000 })
 
 /** 导出已训练模型权重 */
 export const exportModelUrl = (modelName: string) =>