Restore startPipeline after inserting reprocessPipeline.

The function header was dropped, which left a return at module scope and broke the Next.js build.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/api.ts

@@ -455,6 +455,8 @@ export async function reprocessPipeline(
   }
   return res.json();
 }
+
+export async function startPipeline(projectId: string) {
   const res = await authFetch(`${BASE}/api/pipeline/${projectId}/start`, {
     method: "POST",
   });