Extend the spec with IO scanning functions (scan-io-refs, transitive-io-refs,
compute-all-io-refs, component-pure?) that detect IO primitive references in
component ASTs. Components are classified as pure (no IO deps, safe for client
rendering) or IO-dependent (must expand server-side).
The partial evaluator (_aser) now uses per-component IO metadata instead of
the global _expand_components toggle: IO-dependent components expand server-
side, pure components serialize for client. Layout slot context still expands
all components for backwards compat.
Spec: 5 new functions + 2 platform interface additions in deps.sx
Host: io_refs field + is_pure property on Component, compute_all_io_refs()
Bootstrap: both sx_ref.py and sx-ref.js updated with IO functions
Bundle analyzer: shows pure/IO classification per page
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
giles
0ba7ebe349