Don't change any code yet. I want a plan first.

Move all status handling into a new module, tickets/status.py, without
changing behaviour: same CLI output, same errors.

Find every place that knows about statuses: the list, validation, labels.
Then give me a numbered plan where:
- each step changes one or two files,
- `python -m pytest -q` passes after every step,
- the old code stays until nothing uses it, and is deleted in the last step.

For each step, name the files and the test count you expect. Check the
tests cover everything the refactor touches; if something isn't covered,
make step 1 a test that pins its current behaviour.

When I approve the plan, save it to PLAN.md before you touch any code.
