Migrate the production build chain (publish, cache, execution tests) to QuantEcon/mystmd after #363

Goal

Finish what #363 starts: once the JB2 branch lands, the repo should be 100% QuantEcon/mystmd — no jupyter-book 1.x anywhere in the build chain. #363 deliberately migrates only the PR preview (ci.yml) and ipynb builds (build-ipynb.yml); everything production-facing still runs the JB1/Sphinx toolchain from main, driven by lectures/_config.yml + _toc.yml, which #363 replaces with myst.yml. Mixing the two long-term means every lecture edit is validated against one engine and published with another.

What still runs jupyter-book 1.x

Housekeeping in the same sweep: cache.yml is still named "Build Cache [using jupyter-book]", and .github/workflows/_github_actions/ci.yml is a stale stashed copy of the old preview workflow.

Constraints and lessons to carry over (from the #363 incident, 2026-08-03)

Execution-affecting configuration must be inside the execution cache key — hash the workflow file and requirements alongside the lectures, as ci.yml now does, or an engine/env change ships green against stale outputs. Pin the mystmd fork by SHA and JAX by version. Keep XLA_PYTHON_CLIENT_PREALLOCATE=false (or successor policy from QuantEcon/meta#350) on any step that executes the JAX lectures concurrently on a single-GPU runner; the JB1 chain never needed it only because Sphinx executes sequentially. Keep the memory/dmesg telemetry pattern on GPU execution jobs.

Sequencing

This is follow-up work to #363, not part of it — it should land as its own PR(s) after #363 merges, with the PDF export likely the long pole (needs typst template work and visual signoff). Related: QuantEcon/meta#348 (shared build-lectures action) is the natural place for the standardised pieces to land once, and QuantEcon/meta#350 will supply the JAX-on-CI configuration defaults.

Carried over from #344 (consolidated 2026-08-04)

Two mystmd build warnings remain from the #342/#344 tracking pair (both closed in favour of this issue):

• python_oop.md:12 — index directive parse failure: single: OOP II: Building Classes (the second colon breaks parsing). Fix by rewording the entry, e.g. single: OOP II -- Building Classes.
• status.md:16 — unknown directive: nb-exec-table (sphinx-tojupyter only). Needs a mystmd equivalent or a redesign of the execution-status page.

Bắt đầu bằng cách so sánh ci.yml và build-ipynb.yml của #363 với publish.yml, cache.yml, execution-*.yml, environment.yml và lectures/myst.yml. Truy vết cách HTML production, PDF, các lượt tải notebook, bộ nhớ đệm và các bài kiểm tra thực thi hiện đang được build. Công việc được xem là hoàn tất khi các production surface còn lại không còn sử dụng jupyter-book 1.x, bộ nhớ đệm bao gồm các đầu vào ảnh hưởng đến việc thực thi, PDF đã được xem xét trực quan và các cảnh báo mystmd được liệt kê đã được giải quyết.