Delete sx_ref.py — OCaml is the sole SX evaluator

Removes the 5993-line bootstrapped Python evaluator (sx_ref.py) and all
code that depended on it exclusively. Both bootstrappers (JS + OCaml)
now use a new synchronous OCaml bridge (ocaml_sync.py) to run the
transpiler. JS build produces identical output; OCaml bootstrap produces
byte-identical sx_ref.ml.

Key changes:
- New shared/sx/ocaml_sync.py: sync subprocess bridge to sx_server.exe
- hosts/javascript/bootstrap.py: serialize defines → temp file → OCaml eval
- hosts/ocaml/bootstrap.py: same pattern for OCaml transpiler
- shared/sx/{html,async_eval,resolver,jinja_bridge,handlers,pages,deps,helpers}:
  stub or remove sx_ref imports; runtime uses OCaml bridge (SX_USE_OCAML=1)
- sx/sxc/pages: parse defpage/defhandler from AST instead of Python eval
- hosts/ocaml/lib/sx_primitives.ml: append handles non-list 2nd arg per spec
- Deleted: sx_ref.py, async_eval_ref.py, 6 Python test runners, misc ref/ files

Test results: JS 1078/1078, OCaml 1114/1114.
sx_docs SSR has pre-existing rendering issues to investigate separately.

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

hosts/javascript/bootstrap.py

@@ -20,8 +20,8 @@ _PROJECT = os.path.abspath(os.path.join(_HERE, "..", ".."))
 if _PROJECT not in sys.path:
     sys.path.insert(0, _PROJECT)
 
-from shared.sx.parser import parse_all
-from shared.sx.types import Symbol
+import tempfile
+from shared.sx.parser import serialize
 from hosts.javascript.platform import (
     extract_defines,
     ADAPTER_FILES, ADAPTER_DEPS, SPEC_MODULES, SPEC_MODULE_ORDER, EXTENSION_NAMES,
@@ -35,29 +35,23 @@ from hosts.javascript.platform import (
 )
 
 
-_js_sx_env = None  # cached
+_bridge = None  # cached OcamlSync instance
 
 
-def load_js_sx() -> dict:
-    """Load js.sx into an evaluator environment and return it."""
-    global _js_sx_env
-    if _js_sx_env is not None:
-        return _js_sx_env
+def _get_bridge():
+    """Get or create the OCaml sync bridge with transpiler loaded."""
+    global _bridge
+    if _bridge is not None:
+        return _bridge
+    from shared.sx.ocaml_sync import OcamlSync
+    _bridge = OcamlSync()
+    _bridge.load(os.path.join(_HERE, "transpiler.sx"))
+    return _bridge
 
-    js_sx_path = os.path.join(_HERE, "transpiler.sx")
-    with open(js_sx_path) as f:
-        source = f.read()
 
-    exprs = parse_all(source)
-
-    from shared.sx.ref.sx_ref import evaluate, make_env
-
-    env = make_env()
-    for expr in exprs:
-        evaluate(expr, env)
-
-    _js_sx_env = env
-    return env
+def load_js_sx():
+    """Load js.sx transpiler into the OCaml kernel. Returns the bridge."""
+    return _get_bridge()
 
 
 def compile_ref_to_js(
@@ -75,16 +69,13 @@ def compile_ref_to_js(
         spec_modules: List of spec modules (deps, router, signals). None = auto.
     """
     from datetime import datetime, timezone
-    from shared.sx.ref.sx_ref import evaluate
 
-    ref_dir = os.path.join(_PROJECT, "shared", "sx", "ref")
-    # Source directories: core spec, web framework, and legacy ref (for bootstrapper tools)
+    # Source directories: core spec and web framework
     _source_dirs = [
         os.path.join(_PROJECT, "spec"),      # Core spec
         os.path.join(_PROJECT, "web"),        # Web framework
-        ref_dir,                              # Legacy location (fallback)
     ]
-    env = load_js_sx()
+    bridge = _get_bridge()
 
     # Resolve adapter set
     if adapters is None:
@@ -219,11 +210,16 @@ def compile_ref_to_js(
         sx_defines = [[name, expr] for name, expr in defines]
 
         parts.append(f"\n  // === Transpiled from {label} ===\n")
-        env["_defines"] = sx_defines
-        result = evaluate(
-            [Symbol("js-translate-file"), Symbol("_defines")],
-            env,
-        )
+        # Serialize defines to SX, write to temp file, load into OCaml kernel
+        defines_sx = serialize(sx_defines)
+        with tempfile.NamedTemporaryFile(mode="w", suffix=".sx", delete=False) as tmp:
+            tmp.write(f"(define _defines \'{defines_sx})\n")
+            tmp_path = tmp.name
+        try:
+            bridge.load(tmp_path)
+        finally:
+            os.unlink(tmp_path)
+        result = bridge.eval("(js-translate-file _defines)")
         parts.append(result)
 
     # Platform JS for selected adapters