sx: step 11 — migrate prolog hook + add worker plugin

Move `hs-prolog-hook` / `hs-set-prolog-hook!` / `prolog` out of
`lib/hyperscript/runtime.sx` into a self-contained plugin file at
`lib/hyperscript/plugins/prolog.sx`. The API surface is preserved —
`lib/prolog/hs-bridge.sx::pl-install-hs-hook!` still calls
`hs-set-prolog-hook!` exactly as before, just resolved to the plugin
file's binding rather than runtime.sx's.

Move the E39 worker stub registration out of `lib/hyperscript/parser.sx`
into `lib/hyperscript/plugins/worker.sx`. The plugin calls
`(hs-register-feature! "worker" ...)` at file load time. Behaviour is
identical — `worker MyWorker ...` raises the same helpful "plugin not
installed" error, just routed through the registry from a separate
file. The pre-existing `behavioral` test for the helpful error
("raises a helpful error when the worker plugin is not installed")
still passes via the new path.

Wire-up:
- OCaml `bin/run_tests.ml`: load `plugins/worker.sx` and
  `plugins/prolog.sx` after `runtime.sx`, before `integration.sx`.
- JS `tests/hs-kernel-eval.js`: extend HS module list with
  `hs-worker` / `hs-prolog`; add `HS_PLUGINS` resolver branch so the
  `hs-` prefix maps to `lib/hyperscript/plugins/`.
- WASM `hosts/ocaml/browser/bundle.sh`: copy plugin files into
  `dist/sx/hs-<name>.sx`.
- WASM `hosts/ocaml/browser/compile-modules.js`: add `hs-worker` /
  `hs-prolog` to `FILES`, `HS_DEPS`, and `HS_LAZY` so the lazy loader
  resolves them on first reference.
- Worker plugin carries a sentinel `(define hs-worker-loaded? true)`
  so `extractDefines` indexes it in the module manifest (the lazy
  loader skips files with no defines).

Mirrors `shared/static/wasm/sx/hs-{parser,runtime}.sx` are byte-identical
to source; new mirrors `hs-{prolog,worker}.sx` written via sx_write_file.

OCaml: 4545 passed, 1339 failed — matches baseline.
JS: 2591 passed, 2465 failed — matches baseline.
Smoke tests: `(prolog ...)` raises "prolog hook not installed" cleanly,
`(hs-set-prolog-hook! ...)` then `(prolog ...)` returns the hook result,
`(hs-compile "worker MyWorker def noop() end end")` raises the worker
stub error via the registry path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

hosts/ocaml/bin/run_tests.ml

@@ -2899,6 +2899,9 @@ let run_spec_tests env test_files =
   load_module "parser.sx" hs_dir;
   load_module "compiler.sx" hs_dir;
   load_module "runtime.sx" hs_dir;
+  let hs_plugins_dir = Filename.concat hs_dir "plugins" in
+  load_module "worker.sx" hs_plugins_dir;
+  load_module "prolog.sx" hs_plugins_dir;
   load_module "integration.sx" hs_dir;
   load_module "htmx.sx" hs_dir;
   (* Override console-log to avoid str on circular mock DOM refs *)

hosts/ocaml/browser/bundle.sh

@@ -75,6 +75,9 @@ cp "$ROOT/shared/sx/templates/tw.sx"        "$DIST/sx/"
 for f in tokenizer parser compiler runtime integration htmx; do
   cp "$ROOT/lib/hyperscript/$f.sx" "$DIST/sx/hs-$f.sx"
 done
+for f in worker prolog; do
+  cp "$ROOT/lib/hyperscript/plugins/$f.sx" "$DIST/sx/hs-$f.sx"
+done
 
 # Summary
 WASM_SIZE=$(du -sh "$DIST/sx_browser.bc.wasm.assets" | cut -f1)

hosts/ocaml/browser/compile-modules.js

@@ -85,6 +85,7 @@ const FILES = [
   'harness-web.sx', 'engine.sx', 'orchestration.sx',
   // Hyperscript modules — loaded on demand via transparent lazy loader
   'hs-tokenizer.sx', 'hs-parser.sx', 'hs-compiler.sx', 'hs-runtime.sx',
+  'hs-worker.sx', 'hs-prolog.sx',
   'hs-integration.sx', 'hs-htmx.sx',
   'boot.sx',
 ];
@@ -455,8 +456,10 @@ for (const file of FILES) {
         'hs-parser': ['hs-tokenizer'],
         'hs-compiler': ['hs-tokenizer', 'hs-parser'],
         'hs-runtime': ['hs-tokenizer', 'hs-parser', 'hs-compiler'],
-        'hs-integration': ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime'],
-        'hs-htmx': ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime', 'hs-integration'],
+        'hs-worker': ['hs-tokenizer', 'hs-parser'],
+        'hs-prolog': ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime'],
+        'hs-integration': ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime', 'hs-worker', 'hs-prolog'],
+        'hs-htmx': ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime', 'hs-worker', 'hs-prolog', 'hs-integration'],
       };
       manifest[key] = {
         file: sxbcFile,
@@ -477,7 +480,7 @@ if (entryFile) {
   const lazyDeps = entryFile.deps.filter(d => LAZY_ENTRY_DEPS.has(d));
   // Hyperscript modules aren't define-library, so not auto-detected as deps.
   // Load them lazily after boot — eager loading breaks the boot sequence.
-  const HS_LAZY = ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime', 'hs-integration', 'hs-htmx'];
+  const HS_LAZY = ['hs-tokenizer', 'hs-parser', 'hs-compiler', 'hs-runtime', 'hs-worker', 'hs-prolog', 'hs-integration', 'hs-htmx'];
   for (const m of HS_LAZY) {
     if (manifest[m] && !lazyDeps.includes(m)) lazyDeps.push(m);
   }