Replaces the runTurn/callModel/Anthropic-API-key path in POST /turn with
runClaudeTurn (claude CLI) backed by a per-turn MCP config that spawns
companion-stdio.js. Extracts pending_change_id from tool_result events
defensively (structuredContent → text-JSON fallback). Rewrites companion
test to inject fake-claude-draft.js via app.locals.claudeExe.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Implements runClaudeTurn() — spawns the claude CLI for a single companion
turn using subscription/OAuth auth (strips ANTHROPIC_API_KEY +
ANTHROPIC_AUTH_TOKEN from child env), streaming normalised events (delta,
tool, tool_result, result, error) via onEvent callback.
Includes hermetic test + fake-claude.js fixture that mimics real 2.1.159
stream-json output; zero network/CLI calls in the test suite.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
