A browser that died between two tests left the next one only 'Target page, context or browser has been closed': Playwright logs a browser's stderr and exit only on the pw:browser debug channel, which CI leaves off. Each worker now keeps that channel as a bounded tail, prints one pm-browser-exit| line on an abnormal exit and attaches the tail as browser-stderr.txt to a test that fails on a closed or crashed target. Nothing is retried or hidden. Refs #513