docs(automation): name the source of the approval status list (#3786)

The docs-drift check turned up a FOURTH copy of the status set, in the highest-
visibility place: `automation/approvals.mdx`'s "Statuses in full" line. Unlike
the CORS case in #4282 this one is correct today — all five values, same order —
so there is nothing to fix, only something unguarded.

Points at APPROVAL_STATUSES and says plainly that this line is a copy nothing
updates automatically. That is weaker than derivation and I am not pretending
otherwise: prose docs legitimately restate values, and a path-coupled test
asserting this exact sentence would be brittle. Recorded as a follow-up instead —
`check:variant-docs` already solves this shape for schema variants and is the
right place to extend if the set starts moving.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UXGj3Z5TmwSV6RK2oGc3cb

Author: Claude

content/docs/automation/approvals.mdx

@@ -395,7 +395,11 @@ On finalization the request row gets `status: 'approved'` (or `'rejected'`),
 mirrored to the same value, and the record unlocks. The parked run resumes down
 the `approve` or `reject` branch.
 
-Statuses in full: `pending`, `approved`, `rejected`, `recalled`, `returned`.
+Statuses in full: `pending`, `approved`, `rejected`, `recalled`, `returned` —
+the `APPROVAL_STATUSES` constant in `@objectstack/spec/contracts`, which is also
+what `sys_approval_request.status` offers and what `ApprovalStatus` is derived
+from. If you add a status there, this line is a fourth copy that nothing updates
+for you.
 
 </Steps>