Allow editing metadata of generated document versions

Title, document type, and classification on generated documents could
not be changed: any version-tracked field on a GENERATED write-mode
document was rejected with ErrDocumentVersionGenerated. The error now
fires only when content is being changed, so manual metadata edits
flow through the same draft-on-edit path as authored documents and
produce a draft version that the user can review and publish.

The CLI document update --document-type enum gains
STATEMENT_OF_APPLICABILITY (which generated SoA documents already
use), and the GraphQL resolver maps the content-edit rejection to a
Conflict instead of falling through to a generic Internal error.

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

pkg/server/api/console/v1/document_resolvers.go

@@ -864,6 +864,9 @@ func (r *mutationResolver) UpdateDocument(ctx context.Context, input types.Updat
 		if errArchived, ok := errors.AsType[*probo.ErrDocumentArchived](err); ok {
 			return nil, gqlutils.Conflict(ctx, errArchived)
 		}
+		if errGenerated, ok := errors.AsType[*probo.ErrDocumentVersionGenerated](err); ok {
+			return nil, gqlutils.Conflict(ctx, errGenerated)
+		}
 		if validationErrors, ok := errors.AsType[validator.ValidationErrors](err); ok {
 			return nil, gqlutils.InvalidValidationErrors(ctx, validationErrors)
 		}