Restructure the repository around one naming rule

[Powfu-zwx]

Root cause

The repository carried three language-suffix conventions at once (.zh, -zh, _en), and bare meant English in two places and Chinese in fifty-eight. Chapter files also had three spellings per edition (_experiments, a bare English name, pg / ac abbreviations). Every new page had to pick a convention, and five catalog tables were maintained by hand, so they drifted.

Change

One naming rule: Chinese is the source edition and English its translation. An unsuffixed file is Chinese, -en is English — for text, PDF and notebook alike (dqn.tex / dqn-en.tex). tools/chapters.py is the only place that turns a chapter into a path.

• Delete the unused issue templates, CODEOWNERS, and the old .zh entry points.
• Move scripts/ to tools/, check_consistency.py to check_repo.py, and book/requirements-site.txt to the repository root.
• Add book/chapters.yml as the single chapter list. tools/sync_pages.py generates the four catalog tables and book/_toc.yml from it.
• Split the demo into demo.md and demo-en.md; drop the page's private data-zh / data-en layer and its own language buttons.
• Reduce the language switch to one rule, add or strip -en, and derive each sidebar part's language from its links instead of a caption dictionary.
• Drop the figure-placement assertion and the per-URL catalog assertions. Both guarded prose the generator now owns; the catalog is now checked by regenerating and comparing.
• Move the chapter writing template to docs/rl-note-template.tex, so book/notes/ holds chapters only.
• Describe the project as lecture notes rather than a textbook.

Net: 112 files, +1246 / −1324.

Verification

All five gates pass locally on the built site:

python tools/check_repo.py        # 14 chapters, 28 notebooks, 28 TeX, 42 figures
python tools/check_site.py book/_build/html   # 38 HTML pages and local links
node tools/test_lang_toggle.js    # 18 pairs derived from the repository
python tools/test_colab_setup.py  # Colab bootstrap unit tests
jupyter-book build book           # build succeeded

check_catalog now regenerates each catalog block from book/chapters.yml and compares byte for byte, so a stale table fails CI instead of drifting.

Cleanup

No backups, temporary files, or dead paths left. The only remaining scripts/ mention is the pinned Colab raw URL in tools/colab_setup.py, which points at the v1.2.2 tag's tree layout; a comment there says so, and bumping RELEASE_TAG means repointing the path.

Residual risk

• Chinese is now the default README, home page and site language. Reversible in one step: flip the EDITIONS suffix map in tools/chapters.py, run python tools/sync_pages.py, rebuild.
• Known content defect, deliberately not fixed here: gymnasium 1.3.0 raises DeprecatedEnv for CliffWalking-v0, which temporal-difference-learning and model-based-rl still use in code cells (both languages). Those four notebooks cannot be re-run as committed. Fixing it means re-running two chapters of experiments, re-exporting figures, and reconciling numbers in the text and the Failure Atlas — content work, not structure. python tools/test_colab_setup.py --smoke reports it; CI does not run --smoke.

🤖 Generated with Claude Code