Gitea renders mermaid inline, so the flow/state/hierarchy/DAG diagrams
move to text-in-markdown: auto-layout (removes the manual overlap-prone
draw.io step), diffable source, no committed binaries, and a dark-text
theme so labels stay legible. Keep draw.io PNGs only for the two complex
bespoke diagrams (logical architecture, env2 topology) where pixel
control still wins. All 24 mermaid blocks validated by rendering.
Replace ASCII-art diagrams across the README and docs/ with editable
.drawio sources plus exported PNGs, so the diagrams render clearly in
rendered markdown and can be maintained/regenerated instead of being
hand-edited as fragile text art. Non-diagram blocks (code, folder
trees, UI wireframes) were left as text.