Move defstyle/deftype/defeffect to web-forms.sx — domain forms, not core

These are domain definition forms (same pattern as defhandler, defpage,
etc.), not core language constructs. Moving them to web-forms.sx keeps
the core evaluator + types.sx cleaner for WASM compilation.

web-forms.sx now loaded in both JS and Python build pipelines.

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

hosts/python/bootstrap.py

@@ -1498,6 +1498,7 @@ def compile_ref_to_py(
     sx_files = [
         ("evaluator.sx", "evaluator (frames + eval + CEK)"),
         ("forms.sx", "forms (server definition forms)"),
+        ("web-forms.sx", "web-forms (defstyle, deftype, defeffect, defrelation)"),
         ("render.sx", "render (core)"),
     ]
     # Parser before html/sx — provides serialize used by adapters