deps.sx: scan island bodies for component deps (was only scanning
"component" and "macro", missing "island" type). This ensures
~cssx/tw and its dependencies are sent to the client for islands.
cssx.sx: move if inside make-spread arg so it's evaluated by
eval-expr (no reactive wrapping) instead of render-to-dom which
applies reactive-if inside island scope, converting the spread
into a fragment and losing the class attrs.
Added island dep tests at 3 levels: test-deps.sx (spec),
test_deps.py (Python), test_parity.py (ref vs fallback).
sx-browser.js: temporary debug logging at spread detection points.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>