Module / package name conflicts - rename local modules to avoid import collisions

Problem

Local modules under src/bot use names that collide with standard or third-party packages (e.g. git.py, csv.py, gitlab.py), which can cause import confusion in some environments.

Proposal

Rename local modules to avoid collisions, e.g. git_utils.py, csv_utils.py, gitlab_utils.py. Update imports accordingly and add a short note in the contribution guide.

Impact

Low-complexity change that prevents environment-dependent import errors and makes the codebase more robust.