feat: 后台添加大模型配置管理页面

- 新增 /admin/llm_config 页面
- 支持配置API地址、Key、模型名称、参数
- 支持测试连接和恢复默认配置
- 配置保存到数据库，翻译服务动态读取
- 所有后台页面侧边栏添加入口

admin.py

@@ -661,4 +661,110 @@ def api_user_add_package(user_id):
         'id': user_package.id,
         'name': user_package.package_name,
         'remaining': user_package.remaining_count
-    }})
+    }})
+
+
+# ==================== LLM大模型配置 ====================
+@admin_bp.route('/llm_config')
+@admin_required
+def llm_config():
+    """LLM配置页面"""
+    from config import LLM_CONFIG
+    
+    # 从数据库获取配置，如果没有则使用默认值
+    config = {
+        'api_base': DynamicConfig.get('llm_api_base', LLM_CONFIG.get('api_base')),
+        'api_key': DynamicConfig.get('llm_api_key', LLM_CONFIG.get('api_key')),
+        'model': DynamicConfig.get('llm_model', LLM_CONFIG.get('model')),
+        'max_tokens': DynamicConfig.get('llm_max_tokens', LLM_CONFIG.get('max_tokens')),
+        'chunk_size': DynamicConfig.get('llm_chunk_size', LLM_CONFIG.get('chunk_size')),
+        'timeout': DynamicConfig.get('llm_timeout', LLM_CONFIG.get('timeout')),
+    }
+    
+    return render_template('admin/llm_config.html', config=config)
+
+
+@admin_bp.route('/llm_config/save', methods=['POST'])
+@admin_required
+def save_llm_config():
+    """保存LLM配置"""
+    data = request.json
+    
+    DynamicConfig.set('llm_api_base', data.get('api_base'), category='llm', user_id=session.get('user_id'))
+    DynamicConfig.set('llm_api_key', data.get('api_key'), category='llm', user_id=session.get('user_id'))
+    DynamicConfig.set('llm_model', data.get('model'), category='llm', user_id=session.get('user_id'))
+    DynamicConfig.set('llm_max_tokens', data.get('max_tokens'), category='llm', value_type='int', user_id=session.get('user_id'))
+    DynamicConfig.set('llm_chunk_size', data.get('chunk_size'), category='llm', value_type='int', user_id=session.get('user_id'))
+    DynamicConfig.set('llm_timeout', data.get('timeout'), category='llm', value_type='int', user_id=session.get('user_id'))
+    
+    # 记录日志
+    log = OperationLog(
+        user_id=session.get('user_id'),
+        username='admin',
+        action='update_llm_config',
+        detail='更新大模型配置'
+    )
+    db.session.add(log)
+    db.session.commit()
+    
+    return jsonify({'success': True})
+
+
+@admin_bp.route('/llm_config/test', methods=['POST'])
+@admin_required
+def test_llm_connection():
+    """测试LLM连接"""
+    data = request.json
+    
+    try:
+        from openai import OpenAI
+        
+        client = OpenAI(
+            api_key=data.get('api_key', 'sk-test'),
+            base_url=data.get('api_base'),
+        )
+        
+        # 发送简单测试请求
+        response = client.chat.completions.create(
+            model=data.get('model'),
+            messages=[{"role": "user", "content": "Hello"}],
+            max_tokens=10,
+            timeout=10,
+        )
+        
+        return jsonify({
+            'success': True,
+            'model': data.get('model'),
+            'response': response.choices[0].message.content[:50] if response.choices else 'OK'
+        })
+        
+    except Exception as e:
+        return jsonify({'success': False, 'error': str(e)})
+
+
+@admin_bp.route('/llm_config/reset', methods=['POST'])
+@admin_required
+def reset_llm_config():
+    """恢复默认LLM配置"""
+    from config import LLM_CONFIG
+    
+    # 删除数据库中的LLM配置
+    DynamicConfig.query.filter_by(category='llm').delete()
+    db.session.commit()
+    
+    return jsonify({'success': True})
+
+
+# ==================== 获取当前LLM配置（供其他模块使用） ====================
+def get_llm_config():
+    """获取当前LLM配置"""
+    from config import LLM_CONFIG
+    
+    return {
+        'api_base': DynamicConfig.get('llm_api_base', LLM_CONFIG.get('api_base')),
+        'api_key': DynamicConfig.get('llm_api_key', LLM_CONFIG.get('api_key')),
+        'model': DynamicConfig.get('llm_model', LLM_CONFIG.get('model')),
+        'max_tokens': DynamicConfig.get('llm_max_tokens', LLM_CONFIG.get('max_tokens')),
+        'chunk_size': DynamicConfig.get('llm_chunk_size', LLM_CONFIG.get('chunk_size')),
+        'timeout': DynamicConfig.get('llm_timeout', LLM_CONFIG.get('timeout')),
+    }