Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Drives the extension's returned ThreadController API + asserts the on-disk sidecar and rendered Comments state (spec §6.8 fallback). All 4 host tests green against VS Code 1.124.0. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>