feat: 用户个人中心功能

- 账户余额显示和管理
- 充值功能（模拟模式）
- 退款申请功能（需管理员审核）
- 账户流水记录查看
- 会员购买记录查看
- 使用统计展示
- 新增模型：UserRecharge, UserRefund, MembershipPurchase, AccountTransaction
- User模型添加balance字段
- 导航栏添加个人中心入口

app.py

@@ -14,7 +14,8 @@ from werkzeug.utils import secure_filename
 
 from config import *
 from models import (db, User, Translation, TranslationCache, GuestTranslation, 
-                   DataPackage, UserPackage, DynamicConfig)
+                   DataPackage, UserPackage, DynamicConfig, UserRecharge, UserRefund,
+                   MembershipPurchase, AccountTransaction)
 from services import TranslationService, CacheService, TranslationTask
 from admin import admin_bp
 
@@ -210,6 +211,24 @@ def pricing():
     return render_template('pricing.html', plans=MEMBERSHIP_PLANS, user=user)
 
 
+@app.route('/profile')
+def profile():
+    """个人中心"""
+    user = get_current_user()
+    if not user:
+        return redirect(url_for('login'))
+    
+    limits = USER_LIMITS.get(user.user_type, USER_LIMITS['free'])
+    daily_remaining = limits['daily_translations'] - user.daily_count if limits['daily_translations'] > 0 else '无限'
+    max_pages = limits['max_pages'] if limits['max_pages'] > 0 else '无限'
+    
+    return render_template('profile.html', 
+        user=user,
+        daily_remaining=daily_remaining,
+        max_pages=max_pages
+    )
+
+
 # ==================== 路由: API ====================
 @app.route('/api/upload', methods=['POST'])
 def upload_pdf():
@@ -552,6 +571,145 @@ def user_info():
     })
 
 
+# ==================== 个人中心API ====================
+@app.route('/api/profile/transactions')
+def get_transactions():
+    """获取账户流水"""
+    user = get_current_user()
+    if not user:
+        return jsonify({'error': '请登录'}), 401
+    
+    filter_type = request.args.get('type', 'all')
+    
+    query = AccountTransaction.query.filter_by(user_id=user.id)
+    if filter_type != 'all':
+        query = query.filter_by(transaction_type=filter_type)
+    
+    transactions = query.order_by(AccountTransaction.created_at.desc()).limit(50).all()
+    
+    return jsonify({
+        'success': True,
+        'transactions': [t.to_dict() for t in transactions]
+    })
+
+
+@app.route('/api/profile/purchases')
+def get_purchases():
+    """获取会员购买记录"""
+    user = get_current_user()
+    if not user:
+        return jsonify({'error': '请登录'}), 401
+    
+    purchases = MembershipPurchase.query.filter_by(user_id=user.id)\
+        .order_by(MembershipPurchase.created_at.desc()).limit(20).all()
+    
+    return jsonify({
+        'success': True,
+        'purchases': [p.to_dict() for p in purchases]
+    })
+
+
+@app.route('/api/profile/recharge', methods=['POST'])
+def recharge_balance():
+    """充值"""
+    user = get_current_user()
+    if not user:
+        return jsonify({'error': '请登录'}), 401
+    
+    data = request.json
+    amount = float(data.get('amount', 0))
+    payment_method = data.get('payment_method', 'balance')
+    
+    if amount < 10:
+        return jsonify({'error': '充值金额最少10元'}), 400
+    
+    if amount > 10000:
+        return jsonify({'error': '充值金额最多10000元'}), 400
+    
+    balance_before = user.balance
+    
+    # 创建充值记录
+    order_no = f"RC{datetime.now().strftime('%Y%m%d%H%M%S')}{user.id}"
+    recharge = UserRecharge(
+        user_id=user.id,
+        amount=amount,
+        balance_before=balance_before,
+        payment_method=payment_method,
+        status='completed',
+        order_no=order_no,
+        completed_at=datetime.utcnow()
+    )
+    
+    # 更新余额
+    user.balance += amount
+    recharge.balance_after = user.balance
+    
+    db.session.add(recharge)
+    
+    # 创建流水记录
+    transaction = AccountTransaction(
+        user_id=user.id,
+        transaction_type='recharge',
+        amount=amount,
+        balance_before=balance_before,
+        balance_after=user.balance,
+        related_id=recharge.id,
+        related_type='recharge',
+        description=f'充值¥{amount}'
+    )
+    db.session.add(transaction)
+    
+    db.session.commit()
+    
+    return jsonify({
+        'success': True,
+        'balance': user.balance,
+        'recharge_id': recharge.id
+    })
+
+
+@app.route('/api/profile/refund', methods=['POST'])
+def request_refund():
+    """申请退款"""
+    user = get_current_user()
+    if not user:
+        return jsonify({'error': '请登录'}), 401
+    
+    data = request.json
+    amount = float(data.get('amount', 0))
+    reason = data.get('reason', '')
+    
+    if amount <= 0:
+        return jsonify({'error': '退款金额必须大于0'}), 400
+    
+    if amount > user.balance:
+        return jsonify({'error': '退款金额不能超过余额'}), 400
+    
+    if not reason:
+        return jsonify({'error': '请填写退款原因'}), 400
+    
+    balance_before = user.balance
+    
+    # 创建退款申请
+    refund = UserRefund(
+        user_id=user.id,
+        amount=amount,
+        balance_before=balance_before,
+        reason=reason,
+        reason_type='user_request',
+        status='pending'
+    )
+    
+    db.session.add(refund)
+    db.session.commit()
+    
+    return jsonify({
+        'success': True,
+        'refund_id': refund.id,
+        'message': '退款申请已提交，等待管理员审核'
+    })
+
+
 # ==================== 初始化 ====================
 def init_app():
     """初始化应用"""