Git interactive rebase for cleaning up commit history

Feature branch has messy commits ('WIP', 'fix typo', 'actually fix it') that should be cleaned up before merging.

Use interactive rebase to rewrite history (LOCAL ONLY!):

# Rebase last N commits:
git rebase -i HEAD~5

# Or rebase onto a branch point:
git rebase -i main

# Editor opens with commit list:
# pick abc1234 Add user authentication
# pick def5678 WIP
# pick ghi9012 Fix typo in auth
# pick jkl3456 Actually fix the bug
# pick mno7890 Add tests

# Change to:
# pick abc1234 Add user authentication
# squash def5678 WIP
# squash ghi9012 Fix typo in auth
# squash jkl3456 Actually fix the bug
# pick mno7890 Add tests

# Commands:
# pick = keep commit as-is
# squash = merge into previous commit (combine messages)
# fixup = merge into previous commit (discard message)
# reword = keep commit but change message
# edit = pause to amend commit
# drop = delete commit entirely

# After saving, force push YOUR branch:
git push --force-with-lease origin feature-branch

# NEVER rebase commits that others have pulled!
# Only rebase YOUR unpushed or personal branch commits

# Abort if something goes wrong:
git rebase --abort

Clean commit history makes code review easier and git log useful. Each commit should represent one logical change.