v0.9.0

Minor Changes

• 589c22f: Breaking: reset --demo is now reset --unstaged (short alias -u, was -d). The old name is removed, not aliased.

  The flag does the same thing — it leaves the lesson's diff in the working tree as unstaged changes, with HEAD on the parent commit — but it is now named for its effect rather than for who was expected to run it.

  --unstaged also stops skipping the safety checks. It begins with a hard reset, so it discards uncommitted work and unreachable commits like any other reset; it now warns and asks for confirmation first.