docs(cli): record what docs/duplicate-name rests on after ADR-0048 §3.4

Quote §3.4's surviving text into the rule's own docblock and settle the
justification instead of moving it: the clause retires a runtime throw,
and keeps the authoring-hygiene class this lint belongs to. The reason
the message already states is the one that survived, so no wording
change was warranted.

Also names the card the standing severity disagreement is filed as, and
records that the retired framing is still live in this file's header
docblock (out of this card's file surface, reported not edited).

Claude-Session: https://claude.ai/code/session_01QCdUBjM47SxioST9z5Zwdf
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

packages/cli/src/utils/collect-docs.ts

@@ -934,8 +934,23 @@ function bodyDocsOf(packages: unknown, index: number): DocItem[] {
  * cross-package throw is retired"). What survives there is exactly what this
  * is: an authoring-time hygiene lint. ⚠️ That `os build` refuses the shape at
  * all is a standing disagreement with ADR-0048 §3.4 which PREDATES this card
- * and is filed rather than changed here — ⛔ relaxing a refusal that shipped is
- * not a rider on a widening.
+ * and is filed as #19248 rather than changed here — ⛔ relaxing a refusal that
+ * shipped is not a rider on a widening.
+ *
+ * #19248 read §3.4 back and settled the justification rather than moving it.
+ * The clause retires a RUNTIME throw and nothing else — *"The cross-package
+ * **throw is retired**; two distinct packages coexist on the same bare name by
+ * construction."* — while keeping the class this lint belongs to: *"Authoring-time
+ * hygiene — an author shipping two `page/home` in one package — stays covered by
+ * the `naming/namespace-prefix` lint in `os lint`."* So the reason stated above is
+ * the one that survived §3.4, and ⛔ no wording change was warranted. What #19248
+ * left open is the SEVERITY, not the reason: §3.4 hands authoring hygiene to a
+ * warning-only lint while this one is `severity: 'error'`.
+ *
+ * ⚠️ "this module's older framing" above is not gone — it is still live in this
+ * file's HEADER docblock, which states the retired claim as the current reason for
+ * the naming lints. Out of #19248's file surface (it also justifies
+ * `docs/namespace-prefix`), so it is reported, not edited here.
  */
 function lintDocNamesAcrossOwners(
   sets: ReadonlyArray<{ label: string; docs: readonly DocItem[] }>,