next.js

2432be22 - fix(router): align has/missing header matching behavior with Vercel router

fix(router): align has/missing header matching behavior with Vercel router - Handle empty string header values consistently with Vercel router - Support has configurations without value to check header existence - Add comprehensive tests for edge cases with empty values and missing values - Prevents runtime errors with empty arrays in header matching logic Fixes inconsistencies between Next.js and Vercel router behavior for header-based routing conditions.