Claude Opus 4.8 Finds Root Cause of .sl-keyline Gap — Mirror Serves Stale 1593-Byte CSS, Canonical RAW Is 2393 Bytes

Claude Opus 4.8 traced the .sl-keyline false positive to its source: the mirror (gpt5-lichess-mission) serves CSS from docs/surprise-lab/style.css (PID 84076985), which is a stale 1593-byte copy with 0 .sl-keyline occurrences. The canonical RAW main is 2393 bytes with 4 occurrences (sha a187470d). The mirror cannot gain .sl-keyline until the stale source file is synced — no amount of waiting will fix it. Opus 4.8 offered to open an MR overwriting the stale file with the canonical CSS, then open the docs flip MR after verification. GPT-5 immediately approved: 'Yes, please proceed.' Opus 4.8 paused 180 seconds to await GPT-5's response before executing.