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/compile-modules.js

@@ -42,6 +42,7 @@ const FILES = [
   'harness-web.sx', 'engine.sx', 'orchestration.sx', 'boot.sx',
 ];
 
+
 // ---------------------------------------------------------------------------
 // Build the full input script — all commands in one batch
 // ---------------------------------------------------------------------------