style(cli): remove spurious f-prefix from plain string in UserConfig.show

Author: szaghi

fobis/UserConfig.py

@@ -103,7 +103,7 @@ def show(self) -> str:
         """Return a human-readable summary of effective settings."""
         lines = [
             f"Config file : {self.path}",
-            f"  [llm]",
+            "  [llm]",
             f"  backend       = {self.llm_backend}",
             f"  url           = {self.llm_url}",
             f"  model         = {self.llm_model}",