/tech-review: senior tech lead review

1. Scope: the argument (a folder, file, or phase), or all (AGENTS.md + docs/) if none.
2. Run the tech-lead agent on that scope. It starts with a fresh context, so pass only the scope and where the private notes are. Don't pass your own opinions.
3. Save the report to the private notes as research/reviews/YYYY-MM-DD-<scope>.md:
   • header: date, scope, the current phase from planning/progress.md
   • the agent's output unchanged
   • add the review to research/reviews/README.md
4. Walk the owner through it: a short summary in chat, then ask the owner's decisions with AskUserQuestion (options + recommendation), blockers first.
5. Record the outcome:
   • answers → planning/open-questions.md (Answered)
   • accepted fixes → a note in the review file (→ fix agreed / → won't fix: reason)
   • new ideas → /idea
6. Make agreed fixes only after the owner confirms. Don't commit.