Publish Pi4J's Groma architecture map at pi4j.com/groma

[FDelporte]

Summary

• Adds a step to .github/workflows/hugo.yml that checks out Pi4J/pi4j (public, read-only) and runs groma export into static/groma before the Hugo build, so the map ends up published at pi4j.com/groma/ alongside the existing v1/v2 static content.
• Adds a repository_dispatch (groma-architecture-updated) and workflow_dispatch trigger, so the site can be rebuilt on demand instead of only on pushes to this repo.
• Companion change in Pi4J/pi4j: a workflow that sends this repository_dispatch whenever architecture-relevant paths change on its main branch — see Pi4J/pi4j#786.

Requires a one-time manual step

For the automatic rebuild-on-change to work, a maintainer needs to:

1. Create a Personal Access Token with write access to this repo (fine-grained: Contents read + Actions write is enough; classic: repo scope).
2. Add it as a secret named GROMA_WEBSITE_DISPATCH_TOKEN in the Pi4J/pi4j repository's settings (not this one).

Without that secret, this repo's own push-to-main trigger still works as before; the map just won't auto-refresh when only the Pi4J/pi4j code changes.

Test plan

• Merge and confirm the Action run checks out Pi4J/pi4j, exports successfully, and the Hugo build/deploy completes
• Visit https://www.pi4j.com/groma/ and confirm the map loads
• After the companion secret is added, push an architecture-relevant change to Pi4J/pi4j's main and confirm this repo rebuilds via repository_dispatch

🤖 Generated with Claude Code

[Copilot]

Copilot review overview

🟡 Changes recommended

Token permissions, reproducible tool versioning, and concurrent deployment handling need correction.

Review effort: Balanced
Findings: 2 · 1

Open (3)

• Correct PAT permissions to Contents: write · New
• Serialize deployments and cancel superseded runs · New
• Pin Groma version to match the companion workflow · New

What changed in this PR

Publishes Pi4J’s Groma architecture map through the existing Hugo deployment workflow.

Changes:

• Adds manual and repository-dispatch deployment triggers.
• Exports the Pi4J Groma map into Hugo static assets.
• Excludes generated map files from version control.

File	Description
.github/​workflows/​hugo.yml	Adds Groma export and deployment triggers.
.gitignore	Ignores generated Groma assets.

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[Copilot]

The fine-grained PAT instructions should say Contents: write for Pi4J/pi4j.github.io; Actions: write is not required for the repository_dispatch endpoint. The classic repo scope remains unchanged.

[Copilot]

The setup instructions are in the PR description, not a repository file. They should specify a fine-grained PAT with Contents: write for Pi4J/pi4j.github.io; Actions: write is not required for repository_dispatch. The classic PAT repo scope remains unchanged.

[eitch]

the serialization should be done