v0.1.10

Demo shows the lifecycle instead of claiming it:

• New lesson (yellow-leaves-was-the-light) corrects the first one: October blamed the watering, the real cause was the north-facing kitchen.
• The older lesson is now Status: superseded with a Superseded by pointer. Its content is untouched and still readable, which is the point: notes are marked, not deleted.
• topic.md updated to match. Every demo note is no longer 'active', so the central promise is finally demonstrated in what you open on day one.