v0.4.0

The road off statesman: rails generate statecraft:from_statesman Order
converts a statesman setup in place — the table you already have becomes
the statecraft log, history included.

• The generator reflects the live statesman machine and writes the
  conversion migration: the model gains its state column backfilled from
  the last transition by sort_key, the transitions table gains
  from_state (a LAG window along the chain) and a cascade FK, a text
  metadata column becomes native json(b) in one move, and statesman's
  columns and unique indexes retire last.
• A machine skeleton arrives with the graph copied and the human parts
  honestly left open: statesman has no events — name them yourself — and
  guard bodies cannot be extracted, so each becomes a TODO carrying its
  original file:line.
• Refusals are loud: a missing machine class, a class that does not quack
  like statesman, a machine with no initial state.
• The README's new "Migrating from statesman" recipe carries the reasons,
  the two pre-flight checks on live data (id order vs sort_key order;
  text metadata holding valid JSON), and the hand-finished cleanup list.

Full Changelog: v0.3.0...v0.4.0