[BUG] Server-side experiment (x-cc-atis) silently removed Opus 4.8 thinking summaries, and the CLI silently self-updated even with autoUpdates: false. No notice, no opt-in, settings silently overridden.

[BUG] Server-side experiment (x-cc-atis) silently removed Opus 4.8 thinking summaries, and the CLI silently self-updated even with autoUpdates: false. No notice, no opt-in, settings silently overridden. #111266