feat(documents): hide completed workflows from folder views

When listDocuments is called with folderId set (including folderId=null
for root-only), exclude status='completed' rows. The signed-PDF file
appears in the Files section with a "view signing details" link; the
workflow row would just be noise alongside the file.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/lib/services/documents.service.ts

@@ -184,6 +184,10 @@ export async function listDocuments(
     } else {
       filters.push(eq(documents.folderId, query.folderId));
     }
+    // When viewing a specific folder, hide completed workflows — they surface
+    // via their resulting signed-PDF file row in the Files section, not the
+    // Signing section.
+    filters.push(ne(documents.status, 'completed'));
   }
   if (sentSince) filters.push(gte(documents.createdAt, new Date(sentSince)));
   if (sentUntil) filters.push(lte(documents.createdAt, new Date(sentUntil)));