[bseverns]

Motivation

• Allow the p5 sketch to ingest live JSON gesture lines from hardware via WebSerial and forward them to ingestSerialLine(line).
• Provide a minimal teaching-friendly UI so instructors can point at a Connect Serial button and show the serial handshake/status.
• Document exact browser and serving requirements so users can reliably connect from the browser.
• Keep keyboard shortcuts working so the demo still runs without hardware.

Description

• Implemented WebSerial helpers and a small HUD in software/p5js/sketch.js including setupSerialHud(), connectSerial(), startSerialReadLoop(), disconnectSerial(), and related state variables.
• The read loop decodes the serial text stream, splits on newlines, trims lines, and calls ingestSerialLine(trimmedLine) for each full line.
• HUD includes a Connect Serial button, status span, feature detection for navigator.serial, and graceful disconnect/read-error handling.
• Added software/p5js/README.md describing browser requirements, exact local-server steps (python3 -m http.server 8000), connection flow, and the keyboard fallbacks.

Testing

• Started a local HTTP server with python3 -m http.server 8000 to confirm the sketch and README are serveable, which succeeded.
• Attempted an automated headless-browser screenshot using Playwright to smoke-test the page, but Chromium failed to launch in this environment so the capture did not complete.
• No unit tests exist for the sketch; keyboard-triggered gestures (e.g. P, S, B, R) were intentionally left unchanged for manual/demo testing.

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Codex Task