feat(generate): 图片持久化到本地 generation/ 目录，前端对接真实 API

后端:
- POST /api/v1/generate 接收 projectId，生成 taskId，将图片保存至 generation/{projectId}/{taskId}/
- 新增 GET /api/v1/tasks/:taskId 和 GET /api/v1/tasks/:taskId/assets 查询端点
- 添加 /generation 静态文件服务，前端可通过 URL 直接访问生成的图片
- PipelineInput 增加 ProjectID/TaskID 字段

前端:
- generate.ts 对接真实后端 API，移除 mock 模式
- 401 时不再强制登出跳转，改为抛错由调用方处理
- GeneratePage 加载工程风格，传递 projectId 和完整参数
- generation store 简化为同步 API 模式，移除 WebSocket mock
- ResultPage 使用 getTask/getAssets 按 taskId 查询结果

frontend/src/stores/generation.ts

@@ -1,82 +1,74 @@
 import { create } from 'zustand'
-import type { Asset, PipelineProgress, PipelineStage } from '../api/types'
+import type { Asset, GenerateRequest, GenerateResponse } from '../api/types'
 import { submitGenerate } from '../api/generate'
-import { createMockWebSocket } from '../api/mock'
 
 type Status = 'idle' | 'submitting' | 'running' | 'completed' | 'failed'
 
 interface GenerationState {
   taskId: string | null
-  stage: PipelineStage | null
+  projectId: string | null
   progress: number
   status: Status
-  retryCount: number
-  rejectReason: string | null
   assets: Asset[]
   error: string | null
-  submit: (projectId: string, prompt: string, assetType: string) => Promise<void>
-  handleProgress: (msg: PipelineProgress) => void
+  submit: (req: GenerateRequest) => Promise<void>
   reset: () => void
 }
 
-let cleanupWs: (() => void) | null = null
-
-export const useGenerationStore = create<GenerationState>((set, get) => ({
+export const useGenerationStore = create<GenerationState>((set) => ({
   taskId: null,
-  stage: null,
+  projectId: null,
   progress: 0,
   status: 'idle',
-  retryCount: 0,
-  rejectReason: null,
   assets: [],
   error: null,
 
-  submit: async (projectId, prompt, assetType) => {
+  submit: async (req) => {
     set({ status: 'submitting', error: null })
     try {
-      const taskId = await submitGenerate(projectId, prompt, assetType)
-      set({ taskId, status: 'running', progress: 0 })
+      set({ status: 'running', progress: 30 })
+      const result = await submitGenerate(req)
 
-      // 启动 mock WebSocket
-      cleanupWs = createMockWebSocket(
-        taskId,
-        (msg) => get().handleProgress(msg),
-        (assets) => {
-          set({ status: 'completed', assets, progress: 100 })
-        },
-        (error) => {
-          set({ status: 'failed', error })
-        }
-      )
+      set({ progress: 80 })
+      const assets = mapAssets(result)
+
+      set({
+        taskId: result.taskId,
+        projectId: req.projectId,
+        status: 'completed',
+        progress: 100,
+        assets,
+      })
     } catch (err) {
-      set({ status: 'failed', error: (err as Error).message })
-    }
-  },
-
-  handleProgress: (msg) => {
-    set({
-      stage: msg.stage,
-      progress: msg.progress,
-      retryCount: msg.retryCount ?? get().retryCount,
-      rejectReason: msg.rejectReason ?? null,
-    })
-    if (msg.result?.assets) {
-      set({ assets: msg.result.assets })
+      const errMsg = (err as Error).message
+      set({ status: 'failed', error: errMsg })
     }
   },
 
   reset: () => {
-    cleanupWs?.()
-    cleanupWs = null
     set({
       taskId: null,
-      stage: null,
+      projectId: null,
       progress: 0,
       status: 'idle',
-      retryCount: 0,
-      rejectReason: null,
       assets: [],
       error: null,
     })
   },
 }))
+
+function mapAssets(resp: GenerateResponse): Asset[] {
+  return resp.assets.map((a, i) => ({
+    id: `asset-${i}`,
+    url: a.url,
+    format: a.format,
+    width: resp.metadata.frameWidth,
+    height: resp.metadata.frameHeight,
+    metadata: {
+      frameWidth: resp.metadata.frameWidth,
+      frameHeight: resp.metadata.frameHeight,
+      frameCount: resp.metadata.frameCount,
+      directions: resp.metadata.directions,
+    },
+  }))
+}