fix: Include creator in collaboratorIds for document listing

Documents with empty collaboratorIds don't appear in collection sidebar.
Now includes creator's userId in the array.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/tools/documents.ts

@@ -249,7 +249,7 @@ const createDocument: BaseTool<CreateDocumentArgs> = {
           VALUES (
             gen_random_uuid(),
             substring(md5(random()::text) from 1 for 10),
-            $1, $2, $3, $4, $5, $6, $7, $8, $9, NOW(), NOW(), 1, false, false, false, '{}'
+            $1, $2, $3, $4, $5, $6, $7, $8, $9, NOW(), NOW(), 1, false, false, false, ARRAY[$6]::uuid[]
           )
           RETURNING id, "urlId", title, "collectionId", "publishedAt", "createdAt"
         `;