SOA as document: replace export with publish workflow

Statements of Applicability are no longer exported as one-off PDFs.
Instead, each SOA owns a persistent document that accumulates versions
over time, following the same publish/approve lifecycle as authored
documents.

Publishing without approvers publishes immediately; publishing with
approvers creates a draft pending approval via the existing quorum
system. SOAs can also store default approvers that are pre-populated in
the publish dialog.

The SOA is removed from the snapshot system — applicability statements
are now queried directly (snapshot_id IS NULL) rather than through
snapshot copies.

A standalone migration script (cmd/migrate-soa-snapshots-to-documents)
converts existing SOA snapshots into documents with proper ProseMirror
content, preserving version history and approval decisions.

Signed-off-by: Sacha Al Himdani <sacha@getprobo.com>

packages/n8n-node/nodes/Probo/Probo.node.ts

@@ -131,6 +131,11 @@ export class Probo implements INodeType {
 						value: 'risk',
 						description: 'Manage risks',
 					},
+					{
+						name: 'Statement of Applicability',
+						value: 'statementOfApplicability',
+						description: 'Manage statements of applicability',
+					},
 					{
 						name: 'User',
 						value: 'user',