fix(hub): restore project create payload and stabilize integration DB seed

Explorer POST /projects was dropping projectId/folderId/workspaceDir after a
narrowed response shape, breaking admin-explorer. Make seedTestOrganization
idempotent under shared-DB isolation, force single-worker vitest, and align the
OAuth no-membership redirect expectation with authRoutes.

hub/src/admin/routes/explorerRoutes.ts

@@ -155,7 +155,12 @@ export async function registerExplorerRoutes(
         workspaceRoot: config.projectWorkspaceRoot,
         ...(typeof body.folderId === "string" ? { folderId: body.folderId } : {}),
       });
-      return reply.status(201).send({ id: result.projectId, name: body.name });
+      return reply.status(201).send({
+        projectId: result.projectId,
+        folderId: result.folderId,
+        workspaceDir: result.workspaceDir,
+        name: body.name,
+      });
     } catch (err) {
       return handleRouteError(reply, err);
     }