feat(prompt): AI 提示词优化双栏交互

新增 prompt API 模块调用后端 /api/v1/prompt/optimize，PromptEditor
重构为左右双栏布局支持原始/优化提示词对比编辑，默认开启 AI 优化，
用户可关闭开关或手动编辑优化结果后再提交生成。

frontend/src/stores/task.ts

@@ -1,5 +1,7 @@
 import { create } from 'zustand'
 import type { AssetType } from '../api/types'
+import { optimizePrompt, extractTags } from '../api/prompt'
+import { mergeStyles } from '../utils/style'
 
 interface TaskParams {
   resolution: number
@@ -12,10 +14,16 @@ interface TaskState {
   assetType: AssetType
   taskStyle: Record<string, string>
   params: TaskParams
+  enableAI: boolean
+  optimizedPrompt: string | null
+  isOptimizing: boolean
   setPrompt: (text: string) => void
   setAssetType: (type: AssetType) => void
   toggleTaskStyle: (key: string, value: string) => void
   setParams: (params: Partial<TaskParams>) => void
+  setEnableAI: (enable: boolean) => void
+  setOptimizedPrompt: (text: string | null) => void
+  runOptimize: (projectStyle: Record<string, string>) => Promise<void>
   reset: () => void
 }
 
@@ -24,15 +32,18 @@ const DEFAULT_PARAMS: TaskParams = {
   format: 'spritesheet',
 }
 
-export const useTaskStore = create<TaskState>((set) => ({
+export const useTaskStore = create<TaskState>((set, get) => ({
   prompt: '',
   assetType: 'sprite',
   taskStyle: {},
   params: { ...DEFAULT_PARAMS },
+  enableAI: true,
+  optimizedPrompt: null,
+  isOptimizing: false,
 
-  setPrompt: (text) => set({ prompt: text }),
+  setPrompt: (text) => set({ prompt: text, optimizedPrompt: null }),
 
-  setAssetType: (type) => set({ assetType: type }),
+  setAssetType: (type) => set({ assetType: type, optimizedPrompt: null }),
 
   toggleTaskStyle: (key, value) =>
     set(state => {
@@ -42,17 +53,48 @@ export const useTaskStore = create<TaskState>((set) => ({
       } else {
         next[key] = value
       }
-      return { taskStyle: next }
+      return { taskStyle: next, optimizedPrompt: null }
     }),
 
   setParams: (params) =>
     set(state => ({ params: { ...state.params, ...params } })),
 
+  setEnableAI: (enable) => set({ enableAI: enable, optimizedPrompt: null }),
+
+  setOptimizedPrompt: (text) => set({ optimizedPrompt: text }),
+
+  runOptimize: async (projectStyle) => {
+    const { prompt, assetType, taskStyle } = get()
+    if (!prompt.trim()) return
+
+    const mergedStyle = mergeStyles(projectStyle, taskStyle)
+    const tags = extractTags(mergedStyle)
+    if (tags.length === 0) return
+
+    set({ isOptimizing: true })
+    try {
+      const result = await optimizePrompt({
+        tags,
+        assetType,
+        prompt,
+      })
+      set({ optimizedPrompt: result.prompt })
+    } catch (err) {
+      console.error('提示词优化失败:', err)
+      throw err
+    } finally {
+      set({ isOptimizing: false })
+    }
+  },
+
   reset: () =>
     set({
       prompt: '',
       assetType: 'sprite',
       taskStyle: {},
       params: { ...DEFAULT_PARAMS },
+      enableAI: true,
+      optimizedPrompt: null,
+      isOptimizing: false,
     }),
 }))