docs(todo): drop completed new-joiner doc review item

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: dfa1

TODO.md

@@ -3,7 +3,6 @@
 ## Project
 
 - [ ] Move project to a dedicated organization
-- [ ] Review documentation for new joiners
 - [ ] Create website
    - build something like hardwood.dev but for vortex files
 - [ ] **Benchmark publishing** — drop CI workflow, add `bench-publish` script; see [ADR-0006](docs/adr/0006-benchmark-publishing.md).