Add build-all.sh, bytecode test mode — 5 failures with SX_TEST_BYTECODE=1

The hydration bug root cause: .sxbc bytecoded modules break effect
closures. Source-loaded modules work (15/15), bytecoded fail (10/15).

Run: SX_TEST_BYTECODE=1 node hosts/ocaml/browser/test_wasm_native.js

Failing: scoped static class, signal attr initial, reactive-spread,
CSSX in island scope, reactive attr update.

Also adds build-all.sh (full WASM pipeline) and sx_build target="wasm"
MCP tool integration.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/browser/bundle.sh

@@ -65,8 +65,8 @@ cp "$ROOT/web/engine.sx"        "$DIST/sx/"
 cp "$ROOT/web/orchestration.sx" "$DIST/sx/"
 cp "$ROOT/web/boot.sx"          "$DIST/sx/"
 
-# 9. CSSX (stylesheet language)
-cp "$ROOT/sx/sx/cssx.sx"        "$DIST/sx/"
+# 9. CSSX (stylesheet language — runtime with tw, ~cssx/tw, cssx-process-token etc.)
+cp "$ROOT/shared/sx/templates/cssx.sx" "$DIST/sx/"
 
 # Summary
 WASM_SIZE=$(du -sh "$DIST/sx_browser.bc.wasm.assets" | cut -f1)