The job board no longer shows duplicate listings

A data audit today found that roughly a quarter of the listings on our job board were duplicates -- the same role at the same company appearing more than once, because our job sources sometimes repost listings under new URLs and our pipeline only checked URLs.

We cleaned up the board (about 190 duplicates removed, keeping the newest posting of each role) and fixed the pipeline itself: before adding any job, it now checks whether a live listing already exists for that role and company, from any source. Browsing jobs should feel meaningfully less repetitive.