Tests the exact pattern that broke the home stepper: a component
with letrec bindings referenced inside a map callback. The JIT
compiles the callback with closure vars merged into vm_env_ref.
Subsequent renders must use that env, not the caller's globals.
7 tests covering:
- letrec closure var in map callback (fmt function)
- Render, unrelated render, re-render (env not polluted)
- Signal + letrec + map (the stepper pattern)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
57e7ce9fe4