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>

hosts/javascript/platform.py

@@ -1129,6 +1129,9 @@ PRIMITIVES_JS_MODULES: dict[str, str] = {
   PRIMITIVES["context"] = sxContext;
   PRIMITIVES["emit!"] = sxEmit;
   PRIMITIVES["emitted"] = sxEmitted;
+  // Aliases for aser adapter (avoids CEK special form conflict on server)
+  PRIMITIVES["scope-emit!"] = sxEmit;
+  PRIMITIVES["scope-peek"] = sxEmitted;
 ''',
 }
 # Modules to include by default (all)
@@ -2890,6 +2893,7 @@ PLATFORM_ORCHESTRATION_JS = """
 
   function markProcessed(el, key) { el[PROCESSED + key] = true; }
   function isProcessed(el, key) { return !!el[PROCESSED + key]; }
+  function clearProcessed(el, key) { delete el[PROCESSED + key]; }
 
   // --- Script cloning ---