Add sidebar.yml generation script for shopify-dev docs

[kdaviduik]

Summary

• Adds a reusable Node.js script (docs/generate-sidebar.cjs) that generates sidebar.yml files for the shopify-dev repo
• Replaces manual sidebar editing when adding new calver versions of Hydrogen/Hydrogen React docs

Usage

# After building docs (build-docs.sh), generate the sidebar:
node docs/generate-sidebar.cjs hydrogen 2025-10 \
  packages/hydrogen/docs/generated/generated_docs_data.json \
  /path/to/shopify-dev/content/api/hydrogen/2025-10/sidebar.yml

How it works

1. Reads generated_docs_data.json (the build output)
2. Groups entries by category → subCategory
3. Sorts alphabetically within groups
4. Outputs YAML with correct sidebar keys (hydrogen_2025_10) and URL paths
5. Validates input data — fails clearly if the schema has changed

Test plan

• Used this script to generate sidebar.yml for 2025-10 and 2026-01 (both hydrogen and hydrogen-react)
• Verified entry counts match JSON data (88 hydrogen, 43 hydrogen-react)
• Verified YAML keys match existing 2025-07 convention
• Verified URL slugs match existing patterns

🎩 you can see this PR where I used it

[shopify]

Oxygen deployed a preview of your kd-sidebar-generation-script branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 26, 2026 4:19 AM

Learn more about Hydrogen's GitHub integration.

[fredericoo]

we can make this a ts file and run it with node --experimental-strip-types generate-sidebar.ts or even without the flag in node 24.

would also advocate in favour of creating a command in the root package.json to make it more discoverable. it can build docs → generate sidebar

when are we expected to run this? is this automated? id love some more context