Add comprehensive unit tests for V2 modules

[DeepRatAI]

Several V2 modules in src/medex/ need expanded test coverage:

• tools/ module tests
• vision/ analyzer tests
• knowledge/ base tests
• providers/ integration tests

Goal: >80% coverage on all V2 modules.

[MrIridescent]

Hi! I'd like to take a look at this. I'm new to the project but I've fixed similar issues before. I'll submit a PR shortly.

[DeepRatAI]

Hey @MrIridescent , thanks for reaching out and for the willingness to help! This one got resolved in #23 already, but there are other open issues in the repo if you'd like to pick one up. I'd be happy to have you on board.
Gonzalo.