feat: 前端全面对接后端 API（Phase 1 完成）

- 新增基础设施：useOSSUpload Hook、SSEContext Provider、taskStageMapper 工具
- 达人端4页面：任务列表/详情/脚本上传/视频上传对接真实 API
- 代理商端3页面：工作台/审核队列/审核详情对接真实 API
- 品牌方端4页面：项目列表/创建项目/项目详情/Brief配置对接真实 API
- 保留 USE_MOCK 开关，mock 模式下使用类型安全的 mock 数据
- 所有页面添加 loading 骨架屏、SSE 实时更新、错误处理

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/contexts/AuthContext.tsx

@@ -21,7 +21,7 @@ const AuthContext = createContext<AuthContextType | undefined>(undefined)
 const USER_STORAGE_KEY = 'miaosi_user'
 
 // 开发模式：使用 mock 数据
-const USE_MOCK = process.env.NEXT_PUBLIC_USE_MOCK === 'true' || process.env.NODE_ENV === 'development'
+export const USE_MOCK = process.env.NEXT_PUBLIC_USE_MOCK === 'true' || process.env.NODE_ENV === 'development'
 
 // Mock 用户数据
 const MOCK_USERS: Record<string, User & { password: string }> = {

frontend/contexts/SSEContext.tsx

@@ -0,0 +1,125 @@
+'use client'
+
+import { createContext, useContext, useEffect, useRef, useCallback, ReactNode } from 'react'
+import { useAuth } from './AuthContext'
+import { USE_MOCK } from './AuthContext'
+import { getAccessToken } from '@/lib/api'
+
+type SSEEventType = 'task_updated' | 'review_progress' | 'review_completed' | 'new_task' | 'review_decision'
+type SSEHandler = (data: Record<string, unknown>) => void
+
+interface SSEContextType {
+  subscribe: (eventType: SSEEventType, handler: SSEHandler) => () => void
+}
+
+const SSEContext = createContext<SSEContextType | undefined>(undefined)
+
+const API_BASE_URL = process.env.NEXT_PUBLIC_API_BASE_URL || 'http://localhost:8000'
+
+export function SSEProvider({ children }: { children: ReactNode }) {
+  const { isAuthenticated } = useAuth()
+  const listenersRef = useRef<Map<SSEEventType, Set<SSEHandler>>>(new Map())
+  const abortRef = useRef<AbortController | null>(null)
+  const reconnectTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null)
+
+  const dispatch = useCallback((eventType: SSEEventType, data: Record<string, unknown>) => {
+    const handlers = listenersRef.current.get(eventType)
+    if (handlers) {
+      handlers.forEach(handler => handler(data))
+    }
+  }, [])
+
+  const connect = useCallback(async () => {
+    if (USE_MOCK || !isAuthenticated) return
+
+    // 清除旧连接
+    abortRef.current?.abort()
+    const controller = new AbortController()
+    abortRef.current = controller
+
+    try {
+      const token = getAccessToken()
+      if (!token) return
+
+      const response = await fetch(`${API_BASE_URL}/api/v1/sse/events`, {
+        headers: {
+          'Authorization': `Bearer ${token}`,
+          'Accept': 'text/event-stream',
+        },
+        signal: controller.signal,
+      })
+
+      if (!response.ok || !response.body) return
+
+      const reader = response.body.getReader()
+      const decoder = new TextDecoder()
+      let buffer = ''
+
+      while (true) {
+        const { done, value } = await reader.read()
+        if (done) break
+
+        buffer += decoder.decode(value, { stream: true })
+        const lines = buffer.split('\n')
+        buffer = lines.pop() || ''
+
+        let currentEvent = ''
+        let currentData = ''
+
+        for (const line of lines) {
+          if (line.startsWith('event:')) {
+            currentEvent = line.slice(6).trim()
+          } else if (line.startsWith('data:')) {
+            currentData = line.slice(5).trim()
+          } else if (line === '' && currentEvent && currentData) {
+            try {
+              const parsed = JSON.parse(currentData)
+              dispatch(currentEvent as SSEEventType, parsed)
+            } catch {
+              // 忽略解析错误
+            }
+            currentEvent = ''
+            currentData = ''
+          }
+        }
+      }
+    } catch (err) {
+      if (err instanceof DOMException && err.name === 'AbortError') return
+      // 5秒后重连
+      reconnectTimerRef.current = setTimeout(connect, 5000)
+    }
+  }, [isAuthenticated, dispatch])
+
+  useEffect(() => {
+    connect()
+    return () => {
+      abortRef.current?.abort()
+      if (reconnectTimerRef.current) clearTimeout(reconnectTimerRef.current)
+    }
+  }, [connect])
+
+  const subscribe = useCallback((eventType: SSEEventType, handler: SSEHandler): (() => void) => {
+    if (!listenersRef.current.has(eventType)) {
+      listenersRef.current.set(eventType, new Set())
+    }
+    listenersRef.current.get(eventType)!.add(handler)
+
+    return () => {
+      listenersRef.current.get(eventType)?.delete(handler)
+    }
+  }, [])
+
+  return (
+    <SSEContext.Provider value={{ subscribe }}>
+      {children}
+    </SSEContext.Provider>
+  )
+}
+
+export function useSSE() {
+  const context = useContext(SSEContext)
+  if (!context) {
+    throw new Error('useSSE must be used within SSEProvider')
+  }
+  return context
+}