Benchmark report artifact

This is a static report-style HTML artifact: still script-free, but much easier to scan than a raw markdown table dump.

Median latency 2.1s

Steady-state TPS 148

Proof backlog 0

Surface	Markdown-only version	HTML artifact version
Status summary	Linear bullet list	Metrics cards + readable table
Architecture note	Indented headings	Grouped panels and embedded diagrams
Operator handoff	Long checklist	Sectioned report with callouts

Why this matters: HTML is not replacing Markdown authoring everywhere. It is replacing Markdown as the final artifact format when structure, navigation, and readability matter.