fix: register IM read tools when api.config is undefined (#415)

[Hamzaa6296]

Fixes #415

The registerGetMessages function in src/tools/oapi/im/message-read.js
returned false silently when api.config was undefined, preventing
feishu_im_user_get_messages, feishu_im_user_get_thread_messages, and
feishu_im_user_search_messages from being registered.

[CLAassistant]

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[Hamzaa6296]

Hi team!
After digging into the source, I traced the root cause to src/tools/oapi/im/message-read.js — the registerGetMessages function has a silent early return when api.config is undefined:
This causes feishu_im_user_get_messages, feishu_im_user_get_thread_messages, and feishu_im_user_search_messages to be skipped with no error or warning in the logs, while all other tool groups register fine.
I've submitted a PR with this fix. Happy to adjust if the maintainers prefer a different approach
Thanks for the great plugin!