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>
fetchSdkSummary() dynamic-imports the ESM-only SDK and returns its build
version + builtin tool catalog (pure, key-free). Kept vscode-free so it is
unit-testable in Node; test asserts a semver version and the read_files tool.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>