Agent surface demo

Infrastructure check page — not a lesson. Confirms block math, Mermaid fences, a video with a transcript link, and the agent Markdown alternate.

Block math

Coverage ratio for a rectangular panel (illustrative):

$$\frac{W_{\text{finished}}}{W_{\text{pattern}}}=s$$

Mermaid

Video + transcript

Placeholder embed; transcript link is required for video pages.

Transcript