Delete evaluator.py shim: all imports go directly to bootstrapped sx_ref.py

EvalError moved to types.py. All 27 files updated to import eval_expr,
trampoline, call_lambda, etc. directly from shared.sx.ref.sx_ref instead
of through the evaluator.py indirection layer. 320/320 spec tests pass.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/sx/handlers.py

@@ -70,10 +70,7 @@ def load_handler_file(filepath: str, service_name: str) -> list[HandlerDef]:
     """Parse an .sx file, evaluate it, and register any HandlerDef values."""
     from .parser import parse_all
     import os
-    if os.environ.get("SX_USE_REF") == "1":
-        from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
-    else:
-        from .evaluator import _eval as _raw_eval, _trampoline
+    from .ref.sx_ref import eval_expr as _raw_eval, trampoline as _trampoline
     _eval = lambda expr, env: _trampoline(_raw_eval(expr, env))
     from .jinja_bridge import get_component_env