Three root causes for reactive attribute updates not propagating in WASM:
1. `context` CEK special form only searched kont provide frames, missing
`scope-push!` entries in the native scope_stacks hashtable. Unified by
adding scope_stacks fallback to step_sf_context.
2. `flush-subscribers` used bare `(sub)` call which failed to invoke
complex closures in for-each HO callbacks. Changed to `(cek-call sub nil)`.
3. Test eagerly evaluated `(deref s)` before render-to-dom saw it.
Fixed tests to use quoted expressions matching real browser boot.
WASM native: 10/10, WASM shell: 26/26.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
giles
521782d579