Classroom: slow container startup time

[cuihtlauac]

Parent issue: #24

Problem

Teachers report students waiting 5-10 minutes for Codespaces to build containers. With 30 students, that's 30 identical builds in parallel. Class time is lost to progress bars.

Status: Addressed

The two-layer pre-built image strategy already solves this. Students pull a ready-made image rather than building from scratch. Startup is limited to image pull time.

Additionally, devcontainer.json specifies hostRequirements (4 CPUs, 8GB RAM, 32GB storage) which helps Codespaces allocate appropriate resources.

Remaining work

• Consider documenting Codespaces prebuilds for GitHub Classroom use, which would cache the image pull step as well.

[cuihtlauac]

Addressed by design: the two-layer pre-built image strategy means students pull a ready-made image. No build step, no progress bars.