Order an explainer by dependency

Order this explainer by dependency.

Produce:
1. For each concept, what a viewer must already understand to follow it.
2. A dependency-sorted order. Where two orders are both valid, say which is better and why.
3. Concepts that can be dropped because nothing depends on them and they are not the point.
4. The first 30 seconds — what to say before any concept, so the viewer knows why to care.
5. Time per concept, summing to my length.

Then:
- The point of highest drop-off risk — usually the first concept that requires the previous one to have landed.
- What to do there: an example, a recap, or splitting into two videos.

Rules:
- *Assume the viewer level I gave you and do not drift upward.* Explainers fail by becoming accurate at the cost of being followable.
- Introduce a term only where it is needed, never earlier.
- Do not add concepts I did not list. If a dependency is missing from my list, say so — that is the finding.