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.")

gateway/slash_commands.py

@@ -1173,8 +1173,8 @@ class GatewaySlashCommandsMixin:
                                 custom_providers=custom_provs,
                                 load_gateway_config=_load_gateway_config,
                             )
-                        except Exception:
-                            pass
+                        except Exception as exc:
+                            logger.debug("preflight-compression switch warning failed: %s", exc)
 
                         # Update cached agent in-place
                         cached_entry = None
@@ -1376,8 +1376,8 @@ class GatewaySlashCommandsMixin:
                 custom_providers=custom_provs,
                 load_gateway_config=_load_gateway_config,
             )
-        except Exception:
-            pass
+        except Exception as exc:
+            logger.debug("preflight-compression switch warning failed: %s", exc)
 
         async def _finish_switch() -> str:
             """Apply the resolved switch (agent, session, config) and build the reply."""

hermes_cli/context_switch_guard.py

@@ -166,4 +166,4 @@ def enrich_model_switch_warnings_for_gateway(
         messages=messages,
         custom_providers=custom_providers,
         config_context_length=cfg_ctx,
-    )
+    )

tests/hermes_cli/test_context_switch_guard.py

@@ -102,4 +102,4 @@ def test_merge_appends_to_existing_warning(monkeypatch):
     result.warning_message = "expensive"
     merge_preflight_compression_warning(result, agent=agent)
     assert "expensive" in result.warning_message
-    assert "preflight compression" in result.warning_message
+    assert "preflight compression" in result.warning_message

tui_gateway/server.py

@@ -2264,8 +2264,8 @@ def _apply_model_switch(
                 custom_providers=custom_provs,
                 config_context_length=_cfg_ctx,
             )
-        except Exception:
-            pass
+        except Exception as exc:
+            logger.debug("preflight-compression switch warning failed: %s", exc)
 
     if not confirm_expensive_model:
         try:
@@ -2286,7 +2286,7 @@ def _apply_model_switch(
                 confirm_msg = f"{confirm_msg}\n\n{result.warning_message}"
             return {
                 "value": result.new_model,
-                "warning": warning.message,
+                "warning": confirm_msg,
                 "confirm_required": True,
                 "confirm_message": confirm_msg,
             }