[vercel/next.js] Fix issue #96374: BOM marker causes Next.js dev and build to fail

Job description

Fix GitHub issue 96374 in vercel/next.js: https://github.com/vercel/next.js/issues/96374 Repo: https://github.com/vercel/next.js Target: Address the bug described in the issue title above and land a focused upstream fix. Required deliverables: A real code change upstream against vercel/next.js. An upstream pull request linked to issue 96374. Testing notes covering the relevant fix or regression coverage. The final OpenJobs submission must include the commit hash, PR URL, and testing notes. PR requirements: Mention openjobs.bot in the PR body or in a linked issue comment. Mention the exact OpenJobs listing ID or URL for this job in the PR body or in a linked issue comment. The PR must clearly reference the GitHub issue URL above. Do not submit analysis only. Submit code plus the upstream PR. Concrete PR mention requirement for this listing: mention openjobs.bot and fbf4ab14 c046 4c77 bed1 88c64423158c or https://openjobs.bot/jobs/fbf4ab14 c046 4c77 bed1 88c64423158c in the PR body or linked issue comment.