[doc-healer] DDUw improvement: scan recently closed documentation issues to catch deferred gaps

[github-actions]

Problem

DDUw's Step 1b searches only for open documentation issues:

repo:$\{\{ github.repository }} is:issue is:open label:documentation

When a documentation issue is closed — whether as completed (gap fixed elsewhere) or as not_planned (explicitly deferred) — DDUw never sees it. This creates two blind spots:

1. Completed externally: A gap was fixed in a PR, but no [docs] DDUw PR references the issue. DDUw has no way to verify documentation actually landed.
2. Not planned: A gap is explicitly deferred. If a related code change later ships (e.g., the feature gets implemented anyway, or a partial fix is merged), DDUw doesn't know to look for a documentation opportunity.

Example from 2026-03-17

Issue #20968 ("GHES: Create prerequisites guide and troubleshooting runbook for Copilot engine") was closed as not_planned on 2026-03-15. On 2026-03-17, commit #21408 merged and automatically injected configure_gh_for_ghe.sh into all compiled agent jobs — a directly related behavioral change. DDUw did not connect these two events and left the documentation gap in place. The Daily Documentation Healer caught it instead.

Proposed Fix

Add a new sub-step to Step 1b in daily-doc-updater.md:

#### 1c. Scan Recently Closed Documentation Issues

Search for documentation issues closed in the last 7 days:

    repo:$\{\{ github.repository }} is:issue is:closed label:documentation closed:>=YYYY-MM-DD

For each closed issue:
- **closed as completed**: Check whether a `[docs]` PR references it. If not, treat it as an unaddressed gap and follow the normal Step 2 flow.
- **closed as not_planned**: Do not auto-create documentation. Instead, cross-reference the issue's subject matter against commits from the same window (Step 2). If a related code change is found, treat the documentation update as a new gap (decoupled from the original issue decision).

Impact

• Catches documentation gaps that slip through when issues are closed before DDUw runs
• Surfaces behavioral changes (like auto-injection of infra scripts) that are related to explicitly-deferred doc requests
• Does not change DDUw's conservatism around not_planned decisions — it only acts when there is confirmed related code evidence

Related

• Issue GHES: Create prerequisites guide and troubleshooting runbook for Copilot engine #20968 — the GHES case that exposed this gap
• Run §23212553221 — doc-healer run that identified this pattern

Generated by Daily Documentation Healer · ◷

• expires on Mar 20, 2026, 7:35 PM UTC