Fix _os → os in jinja_bridge.py hot reload

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

shared/sx/jinja_bridge.py

@@ -348,7 +348,7 @@ def reload_if_changed() -> None:
                      len(changed_files), (t1 - t0) * 1000)
 
         # Invalidate OCaml bridge component cache so next render reloads
-        if _os.environ.get("SX_USE_OCAML") == "1":
+        if os.environ.get("SX_USE_OCAML") == "1":
             from .ocaml_bridge import _bridge
             if _bridge is not None:
                 _bridge._components_loaded = False
@@ -543,7 +543,7 @@ async def sx_async(source: str, **kwargs: Any) -> str:
     When SX_USE_OCAML=1, renders via the OCaml kernel subprocess which
     yields io-requests back to Python for async fulfillment.
     """
-    if _os.environ.get("SX_USE_OCAML") == "1":
+    if os.environ.get("SX_USE_OCAML") == "1":
         from .ocaml_bridge import get_bridge
         bridge = await get_bridge()
         ctx = dict(kwargs)