Complete docs/engineering/ suite — 12 documents covering company overview,
system architecture, tech stack ADRs, codebase structure, service deep dives,
annotated code walkthroughs, dev setup, engineering workflow, testing strategy,
deployment/ops, SDK guide, and README index. All content verified against
source files. All 82 tasks in openspec/changes/engineering-docs/tasks.md
marked complete.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>