The OCaml `apply` primitive only handled NativeFn, causing swap! to
fail in the WASM browser when called with lambda arguments. Extended
to handle all callable types via _sx_call_fn/_sx_trampoline_fn.
Also fixes:
- Pre-existing build errors from int-interned env.bindings migration
(vm-trace, bytecode-inspect, deps-check, prim-check in sx_server.ml)
- Add #portal-root div to page shell for portal island rendering
- Stepper test scoped to lake area (code-view legitimately shows ~cssx/tw)
- Portal test checks #portal-root instead of #sx-root
- Mark 3 known bugs as test.fixme (event-bridge, resource, isomorphic-nav)
98 passed, 3 skipped, 0 failed.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>