Docs

Probably make a multi-page book, possibly integrated with the Svelte app or not

- [ ] Contribution guide
- [ ] Credits (including Rust and other tech dependencies)
- [ ] Describe different ways of using/interpreting -- what people can access something safely right now, vs if we could modify any road
- [ ] Explain why turn restrictions (and relations) are ignored
- [ ] Define scope (and notable omissions like PT and accessibility/connectivity)
- [ ] Explain use cases with walkthroughs/examples (comparing to current counts, looking for what could be done safely right now, looking for potential demand, understanding detours)
- [ ] How to interpret overall potential demand vs making just a few upgraded edges?
- [ ] Flow chart for how to use it
- [ ] Pipeline diagram of how it works
- [ ] Perf table
- [ ] Intro it as betweenness centrality in different worlds (existing or perfect)
- [ ] Validation against real counts, possibly ignoring absolute and even relative amounts; just checking ordering
- [ ] Explain why one country-wide run is more useful than a bunch of runs in smaller regions
- [ ] Expandable detail sections, explaining how it works, like with the OSM node model (and how node pairs work)
- [ ] Explain why a full traffic assignment model isn't useful
- [ ] Include all references (especially https://npct.github.io/pct-shiny/regions_www/www/static/03a_manual/pct-bike-eng-user-manual-c1.pdf)