implement

Implement the work described by the user in the spec or tickets.

If the work is one SDD sub-issue (its body has ## Files owned and ## Verify), call the Skill tool with "implement-issue" for it instead, and stop here.

Use /tdd where possible, at pre-agreed seams.

Run typechecking regularly, single test files regularly, and the full test suite once at the end.

Once done, use /code-review to review the work.

Commit your work to the current branch.