feat: add position history API and frontend integration

- Add /positions/history API endpoint
- Add position history types and API client
- Add translations for position history page
- Integrate PositionHistory component in App

web/src/lib/api.ts

@@ -29,6 +29,7 @@ import type {
   DebateMessage,
   DebateVote,
   DebatePersonalityInfo,
+  PositionHistoryResponse,
 } from '../types'
 import { CryptoService } from './crypto'
 import { httpClient } from './httpClient'
@@ -775,4 +776,13 @@ export const api = {
     const token = localStorage.getItem('auth_token')
     return new EventSource(`${API_BASE}/debates/${debateId}/stream?token=${token}`)
   },
+
+  // Position History API
+  async getPositionHistory(traderId: string, limit: number = 100): Promise<PositionHistoryResponse> {
+    const result = await httpClient.get<PositionHistoryResponse>(
+      `${API_BASE}/positions/history?trader_id=${traderId}&limit=${limit}`
+    )
+    if (!result.success) throw new Error('获取历史仓位失败')
+    return result.data!
+  },
 }