Drop the deploy root from the environment variables table

[ptr727]

Found on the promotion review.

The operator-facing table listed DEPLOY_ROOT as a GitHub Environment variable while the manifest had just stopped declaring it, so the two disagreed about whether it should exist. No environment carries it and no workflow reads it, because the rsync destination is anchored at the deploy key's confinement root and the workflow names an environment rather than a host path.

The table now says why it is absent, and distinguishes it from the local DEPLOY_ROOT in secrets/<environment>.env, which is a different value and still read. That distinction is the reason the stale row was easy to miss: a repo-wide grep for the name returns eleven hits and ten of them are correct.

This is the fourth finding in this session of prose surviving the behaviour it described, all of them the sweep this repo has a rule for.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Updates the operator-facing “Secrets and variables, per environment” documentation to remove DEPLOY_ROOT from the GitHub Environment variables table, aligning the table with the current deployment workflow and manifest behavior.

Changes:

• Removes DEPLOY_ROOT from the GitHub Environment variables list, leaving HUGO_BASEURL as the only variable in that row.
• Updates the explanatory paragraph to reflect that the deploy root is not an environment variable and clarifies the difference vs the local DEPLOY_ROOT in secrets/<environment>.env.
• Adds an explicit rationale for why DEPLOY_ROOT is intentionally absent from the GitHub Environment table.