OCaml evaluator for page dispatch + handler aser, 83/83 Playwright tests

Major architectural change: page function dispatch and handler execution
now go through the OCaml kernel instead of the Python bootstrapped evaluator.

OCaml integration:
- Page dispatch: bridge.eval() evaluates SX URL expressions (geography, marshes, etc.)
- Handler aser: bridge.aser() serializes handler responses as SX wire format
- _ensure_components loads all .sx files into OCaml kernel (spec, web adapter, handlers)
- defhandler/defpage registered as no-op special forms so handler files load
- helper IO primitive dispatches to Python page helpers + IO handlers
- ok-raw response format for SX wire format (no double-escaping)
- Natural list serialization in eval (no (list ...) wrapper)
- Clean pipe: _read_until_ok always sends io-response on error

SX adapter (aser):
- scope-emit!/scope-peek aliases to avoid CEK special form conflict
- aser-fragment/aser-call: strings starting with "(" pass through unserialized
- Registered cond-scheme?, is-else-clause?, primitive?, get-primitive in kernel
- random-int, parse-int as kernel primitives; json-encode, into via IO bridge

Handler migration:
- All IO calls converted to (helper "name" args...) pattern
- request-arg, request-form, state-get, state-set!, now, component-source etc.
- Fixed bare (effect ...) in island bodies leaking disposer functions as text
- Fixed lower-case → lower, ~search-results → ~examples/search-results

Reactive islands:
- sx-hydrate-islands called after client-side navigation swap
- force-dispose-islands-in for outerHTML swaps (clears hydration markers)
- clear-processed! platform primitive for re-hydration

Content restructuring:
- Design, event bridge, named stores, phase 2 consolidated into reactive overview
- Marshes split into overview + 5 example sub-pages
- Nav links use sx-get/sx-target for client-side navigation

Playwright test suite (sx/tests/test_demos.py):
- 83 tests covering hypermedia demos, reactive islands, marshes, spec explorer
- Server-side rendering, handler interactions, island hydration, navigation

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

sx/sxc/pages/sx_router.py

@@ -150,16 +150,40 @@ async def eval_sx_url(raw_path: str) -> Any:
         page_ast = expr
     else:
         import os
-        if os.environ.get("SX_USE_REF") == "1":
-            from shared.sx.ref.async_eval_ref import async_eval
-        else:
-            from shared.sx.async_eval import async_eval
+        use_ocaml = os.environ.get("SX_USE_OCAML") == "1"
 
-        try:
-            page_ast = await async_eval(expr, env, ctx)
-        except Exception as e:
-            logger.error("SX URL page-fn eval failed for %s: %s", raw_path, e, exc_info=True)
-            return None
+        if use_ocaml:
+            # OCaml kernel — the universal evaluator
+            try:
+                from shared.sx.ocaml_bridge import get_bridge
+                from shared.sx.parser import serialize, parse_all
+
+                bridge = await get_bridge()
+                sx_text = serialize(expr)
+                ocaml_ctx = {"_helper_service": "sx"}
+                result_text = await bridge.eval(sx_text, ctx=ocaml_ctx)
+                if result_text:
+                    parsed = parse_all(result_text)
+                    page_ast = parsed[0] if parsed else []
+                else:
+                    page_ast = []
+            except Exception as e:
+                logger.error("SX URL page-fn eval (OCaml) failed for %s: %s",
+                             raw_path, e, exc_info=True)
+                return None
+        else:
+            # Python fallback
+            if os.environ.get("SX_USE_REF") == "1":
+                from shared.sx.ref.async_eval_ref import async_eval
+            else:
+                from shared.sx.async_eval import async_eval
+
+            try:
+                page_ast = await async_eval(expr, env, ctx)
+            except Exception as e:
+                logger.error("SX URL page-fn eval failed for %s: %s",
+                             raw_path, e, exc_info=True)
+                return None
 
         if page_ast is None:
             page_ast = []