refactor: compress tool hint args handling to two lines

nanobot/agent/loop.py

@@ -163,10 +163,8 @@ class AgentLoop:
     def _tool_hint(tool_calls: list) -> str:
         """Format tool calls as concise hint, e.g. 'web_search("query")'."""
         def _fmt(tc):
-            args = tc.arguments
-            if isinstance(args, list) and args:
-                args = args[0]
-            val = next(iter(args.values()), None) if isinstance(args, dict) and args else None
+            args = (tc.arguments[0] if isinstance(tc.arguments, list) else tc.arguments) or {}
+            val = next(iter(args.values()), None) if isinstance(args, dict) else None
             if not isinstance(val, str):
                 return tc.name
             return f'{tc.name}("{val[:40]}…")' if len(val) > 40 else f'{tc.name}("{val}")'