Move document type from document to document version

Follow the same pattern used for classification: document type now lives
exclusively on DocumentVersion. A migration copies existing values from
documents to their versions. The document filter uses a subquery on the
latest version. All three API surfaces (GraphQL, MCP, CLI), resolvers,
frontend, and e2e tests are updated accordingly.

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

apps/trust/src/pages/OverviewPage.tsx

@@ -64,8 +64,8 @@ const overviewFragment = graphql`
       edges {
         node {
           id
-          ...DocumentRowFragment
           documentType
+          ...DocumentRowFragment
         }
       }
     }