fix: guidebook rendering & zh_CN i18n issues (#1-#5)

[sanchuanhehe]

Fixes five rendering/translation defects in the built guidebook. Verified end-to-end with a local build of EN + zh_CN HTML and LaTeX/PDF, and the catalog consistency check (git diff --exit-code -- locales) is idempotent.

Closes #1
Closes #2
Closes #3
Closes #4
Closes #5

#1 — CJK emphasis (**/_) not rendered

CommonMark flanking rules are designed for Latin text, so _斜体_ between CJK characters and **粗体** next to full-width punctuation (e.g. ：) were left literal.

• New tools/sphinx_ext/cjk_emphasis.py: a parse-time markdown-it scanDelims patch that is CJK-aware. Rules only relax when a CJK character is adjacent to the marker, so Latin text (snake_case, English emphasis) is untouched.
• Parse-level fix → covers source and translations, HTML and PDF.

#2 — GitHub button only pointed at the production repo

• repository_url / edit / issue buttons now point at theopensourceway/guidebook (editorial content).
• Added an icon_links entry (wrench icon) to theopensourceway/production (build toolchain).

#3 — Checklist shown as literal [ ] + excessive spacing

• Enabled MyST colon_fence + tasklist extensions.
• The extension's checkbox <input> sits inside the translatable paragraph and is dropped in translated output, so the checkbox is drawn with a CSS pseudo-element (and the real input hidden). EN and zh_CN now render identically; list spacing tightened.

#4 — GitBook {% hint %} blocks shown as literal text ⚠️ transitional solution

• New tools/convert_gitbook.py, run from prepare-source.sh, rewrites {% hint style="..." %} into MyST admonitions in the staging tree only.
• This is a transitional workaround: it leaves the guidebook submodule untouched so we don't fork editorial content. The proper long-term fix is to convert the syntax upstream in the guidebook repo; once that lands, this script and the corresponding prepare-source.sh step can be removed. Admonition titles are localized automatically via Sphinx's built-in zh_CN catalogs.
• 📌 Follow-up tracked in Move GitBook {% hint %} conversion upstream into the guidebook repo (remove transitional staging workaround) #8 (move the conversion upstream and remove this workaround).

#5 — Untranslated English in zh_CN community-manager-self-care

Root cause: the translations already existed but were flagged #, fuzzy (so Sphinx ignored them and rendered English), and some still carried stale {% hint %} markers.

• Unfuzzied 23 valid translations in self-care + 4 in communication-norms, and stripped the stale GitBook markers.
• Fixed 38 checklist entries that went fuzzy after the [ ] change and dropped the literal [ ] prefix from their msgstr.
• Added an identical column to tools/i18n/catalog_status.py (per issue suggestion GitBook {% hint %} blocks not rendered — displayed as literal text #4) to surface msgstr == source segments.
• Result: untranslated = 0, fuzzy = 0 on the affected pages. The remaining identical segments are bibliography citations intentionally kept in English (consistent with the existing translation convention).

Files

• conf.py — register cjk_emphasis, enable colon_fence/tasklist, repo/icon link options
• _static/custom.css — tasklist checkbox + spacing
• tools/sphinx_ext/cjk_emphasis.py (new) — CJK emphasis patch
• tools/convert_gitbook.py (new) — hint→admonition (transitional)
• tools/prepare-source.sh — invoke the converter
• tools/i18n/catalog_status.py — identical column
• locales/zh_CN/.../*.po — unfuzzy / strip stale markers / fix prefixes