Add hs-htmx module to WASM build — htmx activation was missing

The htmx-boot-subtree! function (defined in lib/hyperscript/htmx.sx)
was never loaded in the browser because hs-htmx.sx wasn't in the
bundle or compile-modules lists. Added to:
- bundle.sh: copy htmx.sx as hs-htmx.sx to dist
- compile-modules.js: compile to hs-htmx.sxbc, add to deps and lazy list

This was the root cause of "Load Content" button not working —
hx-* attributes were never activated because htmx-boot-subtree!
was undefined.

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

hosts/ocaml/browser/bundle.sh

@@ -72,7 +72,7 @@ cp "$ROOT/shared/sx/templates/tw-type.sx"   "$DIST/sx/"
 cp "$ROOT/shared/sx/templates/tw.sx"        "$DIST/sx/"
 
 # 10. Hyperscript
-for f in tokenizer parser compiler runtime integration; do
+for f in tokenizer parser compiler runtime integration htmx; do
   cp "$ROOT/lib/hyperscript/$f.sx" "$DIST/sx/hs-$f.sx"
 done