docs: contract 2 Amendment 1 — company-CRUD capability (S2 follow-up) (#1477)

docs/requirements/native-kanban-sot.md

@@ -514,3 +514,47 @@ itself permits, so that contract does not stretch A1 by interpretation.
    default-open disclosure.
 5. Every other constraint of A1 — §8.1.2's remaining bullets, §8.2 in full,
    and §8.3's other acceptance criteria — is untouched.
+
+## 10. Amendment A3 — capability-holder existence disclosure
+
+**Status:** amendment to Amendment A2, added by reviewed PR together with
+contract 2 Amendment 1 (`rbac-grant-model.md` §8, this PR), under that
+amendment's ruling request (decision owner Jason). It binds if and only if
+contract 2 Amendment 1 ratifies; until then §9.1.2's sole-disclosure rule
+stands unmodified — which is consistent, because until ratification the
+company-CRUD capability class is empty and the carve-out below has no
+holders. Everything in §§1–9 remains binding verbatim, with exactly the one
+express modification below. The detailed contract text lives in
+`rbac-grant-model.md` §8.1; this amendment changes only what A2 itself
+permits, so that contract does not stretch A2 by interpretation.
+
+### 10.1 What A3 modifies in A2
+
+1. **Capability-holder disclosure (narrows §9.1.2's sole-disclosure rule
+   by one carve-out).** §9.1.2 makes the directory the sole permitted
+   existence disclosure and keeps private companies undisclosed to
+   non-granted subjects everywhere. A3 admits exactly one further
+   disclosure channel: a subject holding the company-CRUD capability
+   (contract 2 §8), when exercising the hierarchy schema §5.5 visibility
+   command, learns the target company's existence and its old/new
+   visibility values through the command's redacted actor receipt —
+   success for an existing target (private or directory alike) versus
+   `not_found` for a nonexistent id — bounded exactly as contract 2 §8.1
+   states: no name, slug, structure, content, grant, or membership
+   information, and no read command of any kind. To every other
+   non-granted subject, private companies remain undisclosed everywhere,
+   including the directory; the directory remains the sole
+   existence-disclosure _listing_.
+
+### 10.2 What A3 explicitly does not change
+
+1. The directory itself is unchanged: read-only, directory-class companies
+   only, existence/name/slug only (§9.1.2's enumeration is narrowed for
+   capability holders' receipts, widened for nothing).
+2. No join-request surface, no curation listing, no read command of any
+   family is authorized (§9.2.2 unchanged; a curation listing is a further
+   amendment per contract 2 §8.1).
+3. The canonical audit event for visibility mutations is untouched — it
+   keeps hierarchy schema §5.2's full immutable target snapshot; the
+   capability confers no audit read (contract 2 §8.5).
+4. Every other constraint of A1 and A2 is untouched.