Wire up data_terminal puzzle (Puzzle 3: extract_corporate_data)

Per decision WC4, the world has a data_terminal in server_room and conditional descriptions referencing flag:data_extracted, but no puzzle connects them. Add puzzle: use neural_spike on data_terminal -> set flag data_extracted, add item encrypted_datapad. Room conditional descriptions already exist.

定位现有的谜题定义，以及 data_terminal、neural_spike、server_room 和 flag:data_extracted 的世界条目。了解其他谜题如何设置 flags 和添加 items，然后验证在 data_terminal 上使用 neural_spike 会设置 data_extracted 并添加 encrypted_datapad，同时现有的条件描述会作出响应。

由索引模型根据 Issue 内容生成。