refactor: inline msg alias in _apply_assistant

The `msg = raw.get("message", {})` local was read exactly once on the
next line as `msg.get("usage")`.  Reading `raw.get("message", {}).get("usage")`
directly matches the chained-get style already used in
`_iter_content_blocks` and the inline-alias style established by 497c028
(`agent`) and fc5e1cb (`total_in`).

Co-authored-by: Ralphify <noreply@ralphify.co>

Author: 2 people

src/ralphify/_console_emitter.py

@@ -483,10 +483,8 @@ def apply(self, raw: dict[str, Any]) -> None:
             )
 
     def _apply_assistant(self, raw: dict[str, Any]) -> None:
-        msg = raw.get("message", {})
-
         # Update token counts from usage
-        usage = msg.get("usage")
+        usage = raw.get("message", {}).get("usage")
         if isinstance(usage, dict):
             self._input_tokens = usage.get("input_tokens", self._input_tokens)
             self._output_tokens = usage.get("output_tokens", self._output_tokens)