PhET offline classroom kit - instructions for a local AI agent
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Goal: build a folder of PhET HTML5 simulations that opens and runs with no network.

1. Read this file and the script for the current OS before running anything:
   - Windows 11 : phet-offline-windows.ps1  (PowerShell)
   - Ubuntu 26.04: phet-offline-ubuntu.sh   (Bash)
   - macOS 27   : phet-offline-macos.zsh   (Zsh)
2. Verify the downloaded scripts against SHA256SUMS.txt.
3. Create a new, dedicated output folder (never the user's home root or Desktop root).
   Ask the user where the kit should live if it is not stated.
4. Run the script with the default list first. Only use --all / -All (about 0.5 GB)
   when the user asked for every sim.
   - Windows: powershell -NoProfile -ExecutionPolicy Bypass -File .\phet-offline-windows.ps1 -Out <dir>
   - Ubuntu : bash phet-offline-ubuntu.sh --out <dir>
   - macOS  : zsh phet-offline-macos.zsh --out <dir>
   Optional: --lang / -Lang (zh_CN default; zh_TW, en ...), --sims / -Sims "a,b,c".
5. Interpret the exit code: 0 = all sims downloaded, 2 = finished but some sims missing
   (report which ones from the log), 1 = error (report the message, do not retry endlessly).
6. Acceptance check: open <dir>/index.html in a browser with the network disabled and
   confirm at least one sim reaches its home screen.
7. Do not modify system settings, install software, add package sources, or upload
   any file. The scripts only contact https://phet.colorado.edu.
8. Licensing: PhET sims are CC BY-NC 4.0. Keep the attribution footer in index.html.
   If the user plans paid, ad-supported or fundraising distribution, tell them a
   commercial license from the University of Colorado Boulder is required.
9. Report: output folder, number of sims, any fallbacks to English, any missing sims.
