Document production build and deployment flow

[digiguru]

Summary

• rewrite the README around the current Pure architecture and two-repository production deployment
• document the exact-SHA dispatch from digiguru/presentation to digiguru/digiguru.github.io
• document the GitHub Pages export/deploy path and distinguish it from Vercel previews
• add the production URL prominently: https://art.digiguru.co.uk/presentation/
• add the production URL to package.json homepage metadata
• document key operational watch-outs, including WEBSITE_DISPATCH_TOKEN, Pages ownership, canonical-source rules and the current dispatch-website -> needs: build dependency
• add a narrowly scoped cleanup workflow that runs when it lands on master and removes the obsolete migration/experiment branches plus this PR branch

Important finding

The current dispatch-website job depends on build only, not the separate pure job. The README now states that accurately rather than implying every CI job blocks production dispatch.

Branch cleanup

There are no open PRs in this repository. The remaining non-master branches are merged migration branches, explicitly closed/superseded experiments, or the redundant pre-final Stage 7 branch (agent/stage-7-canonical-sources is 0 commits ahead of master).

Because master is protected and the GitHub connector does not expose direct ref deletion, .github/workflows/cleanup-stale-branches.yml uses the repository GITHUB_TOKEN with contents: write to delete those known refs after this PR lands. Its push trigger is path-scoped to that maintenance workflow, so normal future pushes do not rerun the cleanup.

Validation

Normal repository CI validates the README/package metadata and actionlint validates the cleanup workflow before merge.

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Project	Deployment	Actions	Updated (UTC)
presentation	Ready	Preview	Aug 14, 2026 12:59pm