docs(adr): state the open question 2 resolution in business terms (#20892)

Cut the resolution line under ADR-0006 v4 open question 2 to the
conclusion and what it means for a publisher: new packages default to
org, a re-publish without a visibility choice leaves the package as it
is, and the public marketplace stays an explicit choice. The question's
original text is unchanged.

Claude-Session: https://claude.ai/code/session_01VvcEokUG1tvVxkceYfR5XB
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

docs/adr/0006-project-environment-split.v4.md

@@ -240,7 +240,7 @@ when needed.
 2. **Visibility default for CLI-created packages.** `private` (owner org
    only) — consistent with `sys_package.visibility` default. Explicit
    `objectstack package publish --marketplace` flow to escalate.
-   **Resolved (2026-09-30, #20892): closed as `org`, not `private`.** Maintainer ruling 「同意」 on the director's letter A, recorded on #20900 as comment 5921191703: the create-time default is `org`, and `PackageSchema.visibility` declares `.default('org')` (`packages/spec/src/marketplace/package.zod.ts`, landed in `32d3b3c76e`). The entry above is kept as the position the question was opened with.
+   **Resolved (2026-09-30, #20892): `org`.** A new package is visible to every environment of its owner organization by default, not `private`. Re-publishing without `--visibility` leaves an existing package's visibility unchanged, and listing on the public marketplace remains an explicit choice.
 3. **Multi-package envs in Studio.** The current "Environment detail" page
    assumes one artifact. Phase B+ updates it to list installations and
    show per-package versions.