Git workflow

1. One commit, one purpose

Each commit does exactly one thing. SOLID applies to history too — separation of concerns at the commit level is what makes diffs reviewable, blames meaningful, and reverts safe.

• Don't combine a bugfix with a feature.
• Don't sneak unrelated refactors into a feature commit.
• If a single change spans several concerns, split it (git add -p, multiple commits).
• Prefer many small, focused commits over one large grab-bag.

Good:  Add user export endpoint
       Fix off-by-one in invoice paginator

Bad:   Add user export and fix invoice paginator

2. Commit message format