Pre-create /app/notebooks/{user,examples} with correct ownership
before switching to the spicebook user. Without this, the app crashes
with PermissionError when it tries to create these directories at
runtime.
Update frontend Dockerfile prod stage from Caddy static to Node.js
running Astro SSR server. Configure caddy-docker-proxy labels to
route /api/* to backend and everything else to frontend on the same
domain. Support empty PUBLIC_API_URL for same-origin API calls.
Document architecture, features, quick start, file format, API
endpoints, configuration, roadmap, and tech stack. Include screenshots
of the notebook with AC Bode plot and transient step response.
Switch from query-param routing (/notebook/?id=X) to Astro dynamic
routes (/notebook/rc-lowpass-filter). Add @astrojs/node adapter with
output: 'server' for on-demand route handling.
Fix formatEng/formatAxisValue crash on null values passed by uPlot
axis tick formatters. Add CORS origin for port 4322.
