docs: add online template links - #1

Request changes

P1 — Two generated links target template IDs that are not currently deployed by the online app. The live template API exposes the existing Neural Mechanics ID b15a6036-0e38-4f8f-84ba-8b763c408dc9 and the Saad–Solla ID de684a36-a2d5-440f-bb2b-3c249abb8270, but not the new b38ae9dd-735b-46c4-973f-a850a2a55544 or e399fd7d-e107-44d0-94b6-7e2159392253. Clicking those two CTAs therefore reaches the app's “Template link not found” path unless the online template service is deployed with the new records first. Please either deploy those records or use the live IDs.

P2 — The new tests cover only the English first-graph rendered link; they do not iterate all 16 reproduction pages or verify the Chinese rendered links and IDs. Also, open_template is not included in the i18n required-key assertions. Please add the missing coverage.

Local verification against this PR head: 88 relevant docs/README tests passed and the bilingual Sphinx build succeeded. GitHub Actions run 30783650008 is currently startup_failure with no jobs, so CI still needs a rerun or runner investigation.

Re-reviewed at 9ced321.

Approved:

• Canonical local template IDs remain separate from the deployed online_template_id overrides; Neural Mechanics and Saad–Solla now resolve to the live IDs.
• The build contract covers all 17 rendered pages in both English and Chinese, including hrefs and localized labels; i18n coverage includes open_template.
• Verification: 88 relevant docs tests passed, Ruff passed, both Sphinx builds passed, and all 16 unique rendered template IDs were present in the current live template API.

Note: GitHub Actions run 30793558334 is a startup_failure with zero jobs. This is an infrastructure/check-run issue rather than a code failure, but it may still need a rerun or CI repair before merging.