fix(cli): log instead of swallow preflight-warning errors; consistent TUI warning field

Follow-up to the salvaged preflight-compression warning:
- Replace silent `except Exception: pass` at all 5 guard call sites
  (cli.py x2, gateway/slash_commands.py x2, tui_gateway/server.py) with
  `logger.debug(...)` so signature drift in the guard helper isn't hidden.
- tui_gateway/server.py: set the confirm dict's `warning` field to the
  merged message (was bare expensive-model text) so it matches
  `confirm_message` for any future consumer reading `warning`.
- Add trailing newlines to the two new files.

cli.py

@@ -6946,8 +6946,8 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin):
                     messages=list(self.conversation_history or []),
                     config_context_length=getattr(self.agent, "_config_context_length", None),
                 )
-            except Exception:
-                pass
+            except Exception as exc:
+                logger.debug("preflight-compression switch warning failed: %s", exc)
 
         old_model = self.model
         self.model = result.new_model
@@ -7225,8 +7225,8 @@ class HermesCLI(CLIAgentSetupMixin, CLICommandsMixin):
                     messages=list(self.conversation_history or []),
                     config_context_length=getattr(self.agent, "_config_context_length", None),
                 )
-            except Exception:
-                pass
+            except Exception as exc:
+                logger.debug("preflight-compression switch warning failed: %s", exc)
 
         if not self._confirm_expensive_model_switch(result):
             _cprint("  Model switch cancelled.")