feat: 管线四阶段进度上报 + 图片预览 + Vite 代理

后端:
- pipeline.go: ProgressReporter 回调类型 + WithProgressReporter 注入 context
- nodes.go: 各节点 pre/post handler 调用 reportProgress() 上报阶段进度
- generate.go: TaskResponse 新增 stage 字段，runPipelineBg 注入进度回调

前端:
- vite.config.ts: 添加 /generation 代理到后端静态文件服务
- generation.ts: 轮询读取 stage 字段，暴露 stage/retryCount/rejectReason
- GeneratePage.tsx: ProgressBar 接收真实管线阶段数据

frontend/src/pages/GeneratePage.tsx

@@ -19,9 +19,12 @@ export default function GeneratePage() {
   const { style: projectStyle, loadProject } = useProjectStore()
   const {
     status,
+    stage,
     progress,
     taskId,
     statusText,
+    retryCount,
+    rejectReason,
     submit,
     reset: resetGeneration,
   } = useGenerationStore()
@@ -83,11 +86,11 @@ export default function GeneratePage() {
       ) : (
         <div style={{ display: 'flex', flexDirection: 'column', gap: 24 }}>
           <ProgressBar
-            stage={null}
+            stage={stage}
             progress={progress}
             status={status}
-            retryCount={0}
-            rejectReason={null}
+            retryCount={retryCount}
+            rejectReason={rejectReason}
           />
 
           {status === 'running' && (

frontend/src/stores/generation.ts

@@ -1,5 +1,5 @@
 import { create } from 'zustand'
-import type { Asset, GenerateRequest } from '../api/types'
+import type { Asset, GenerateRequest, PipelineStage } from '../api/types'
 import { submitGenerate, getTask, getAssets } from '../api/generate'
 
 type Status = 'idle' | 'submitting' | 'running' | 'completed' | 'failed'
@@ -7,9 +7,12 @@ type Status = 'idle' | 'submitting' | 'running' | 'completed' | 'failed'
 interface GenerationState {
   taskId: string | null
   projectId: string | null
+  stage: PipelineStage | null
   progress: number
   status: Status
   statusText: string
+  retryCount: number
+  rejectReason: string | null
   assets: Asset[]
   error: string | null
   submit: (req: GenerateRequest) => Promise<void>
@@ -25,18 +28,21 @@ function stopPolling() {
   }
 }
 
-export const useGenerationStore = create<GenerationState>((set, get) => ({
+export const useGenerationStore = create<GenerationState>((set) => ({
   taskId: null,
   projectId: null,
+  stage: null,
   progress: 0,
   status: 'idle',
   statusText: '',
+  retryCount: 0,
+  rejectReason: null,
   assets: [],
   error: null,
 
   submit: async (req) => {
     stopPolling()
-    set({ status: 'submitting', error: null, statusText: '提交中...' })
+    set({ status: 'submitting', error: null, statusText: '提交中...', stage: null })
     try {
       const { taskId } = await submitGenerate(req)
 
@@ -44,24 +50,26 @@ export const useGenerationStore = create<GenerationState>((set, get) => ({
         taskId,
         projectId: req.projectId,
         status: 'running',
-        progress: 10,
+        progress: 5,
+        stage: 'prompt_builder',
         statusText: '任务已提交，等待生成...',
       })
 
-      // 开始轮询进度
       pollTimer = setInterval(async () => {
         try {
           const task = await getTask(taskId)
 
-          set({
-            progress: task.progress ?? get().progress,
+          set((s) => ({
+            stage: task.stage ?? s.stage,
+            progress: task.progress ?? s.progress,
+            retryCount: task.retryCount ?? s.retryCount,
             statusText:
               task.status === 'running'
-                ? '生成中...'
+                ? stageLabel(task.stage)
                 : task.status === 'pending'
                   ? '排队中...'
                   : task.status,
-          })
+          }))
 
           if (task.status === 'completed') {
             stopPolling()
@@ -71,6 +79,7 @@ export const useGenerationStore = create<GenerationState>((set, get) => ({
             set({
               status: 'completed',
               progress: 100,
+              stage: 'format_adapter',
               statusText: '生成完成',
               assets,
             })
@@ -85,7 +94,7 @@ export const useGenerationStore = create<GenerationState>((set, get) => ({
         } catch {
           // 网络错误不中断轮询
         }
-      }, 2000)
+      }, 1500)
     } catch (err) {
       stopPolling()
       set({ status: 'failed', error: (err as Error).message, statusText: '提交失败' })
@@ -97,11 +106,24 @@ export const useGenerationStore = create<GenerationState>((set, get) => ({
     set({
       taskId: null,
       projectId: null,
+      stage: null,
       progress: 0,
       status: 'idle',
       statusText: '',
+      retryCount: 0,
+      rejectReason: null,
       assets: [],
       error: null,
     })
   },
 }))
+
+function stageLabel(stage?: string): string {
+  switch (stage) {
+    case 'prompt_builder': return '优化提示词...'
+    case 'asset_generator': return '生成素材中...'
+    case 'quality_supervisor': return '质检中...'
+    case 'format_adapter': return '格式转换中...'
+    default: return '生成中...'
+  }
+}