fix: use hermes_yaml with yaml fallback; add model column to default config

PyYAML is no longer installed in the Hermes venv since recent updates —
/sl failed at runtime with ModuleNotFoundError: No module named 'yaml'.
Now uses the core hermes_yaml module, falling back to PyYAML when present.

.gitignore

@@ -0,0 +1,2 @@
+__pycache__/
+docs/.bak/

__init__.py

@@ -171,8 +171,9 @@ def _ensure_default_config() -> None:
 # Used by /sl slash command. Survives `hermes update`.
 
 columns:
-  - {field: last_active, width: 10, label: Active}
-  - {field: title, width: 42, label: Title}
+  - {field: last_active, width: 7, label: Active}
+  - {field: title, width: 28, label: Title}
+  - {field: model, width: 14, label: Model}
   - {field: message_count, width: 4, label: Msgs}
   - {field: cache_read_tokens, width: 6, label: Hit}
   - {field: input_tokens, width: 6, label: Miss}
@@ -191,14 +192,18 @@ columns:
 
 def _handle_sl(raw_args: str) -> Optional[str]:
     """Handle /sl [limit] — show recent sessions with custom columns."""
-    import yaml
+    try:
+        from hermes_yaml import safe_load as yaml_safe_load
+    except ImportError:
+        import yaml
+        yaml_safe_load = yaml.safe_load
 
     config_path = _hermes_home() / "session_list_config.yaml"
 
     # Load column config
     try:
         if config_path.exists():
-            cfg = yaml.safe_load(config_path.read_text(encoding="utf-8"))
+            cfg = yaml_safe_load(config_path.read_text(encoding="utf-8"))
             columns = cfg.get("columns", [])
         else:
             columns = []