Document where the code lives: link external repos (arduino, makelab-arduino-lib, signals) from README & textbook

[jonfroehlich]

Summary

The physcomp README (and arguably the textbook/website itself) doesn't clearly state where the code featured in the lessons actually lives. The code is hosted across several separate GitHub repos, but a reader landing on the textbook has no obvious pointer to them.

Why

Much of the textbook references and embeds code (Arduino sketches, the shared Arduino library, Signals examples, p5.js sketches), but the source-of-truth repos are external to this one. Readers, students, and contributors should be able to find them easily — to browse full examples, file issues, or contribute.

External code repos to surface

• Arduino examples — https://github.com/makeabilitylab/arduino
• MakeabilityLab Arduino library (shared .hpp classes used by the sketches: filters, OLED shapes/graphs, joystick, buttons, etc.) — https://github.com/makeabilitylab/makelab-arduino-lib
• Signals — https://github.com/makeabilitylab/signals
• p5.js examples — https://github.com/makeabilitylab/p5js

Proposed

• Add a clearly-labeled "Where the code lives" section to the README listing each external repo and what it contains.
• Consider surfacing the same pointers in the textbook/website itself (e.g. an intro/"about the code" page or footer link), not just the README, so end readers see it too.
• Note the relationship between the repos (e.g. that the Arduino sketches depend on the MakeabilityLab Arduino library).

Related

• Relates to Decide code-embedding strategy (single source of truth vs. alternatives) #100 (code-embedding strategy / single source of truth) — this issue is narrower: it's about documenting where the code is hosted, regardless of the embedding approach chosen there.