fix(config): preserve list-format models in custom_providers normalize

_normalize_custom_provider_entry silently drops the models field when it's
a list. Hand-edited configs (and the shape used by older Hermes versions)
still write models as a plain list of ids, so after the normalize pass the
entry reaches list_authenticated_providers() with no models and /model
shows the provider with (0) models — even though the underlying picker
code handles lists fine.

Convert list-format models into the empty-value dict shape the rest of
the pipeline already expects. Dict-format entries keep passing through
unchanged.

Repro (before the fix):

    custom_providers:
    - name: acme
      base_url: https://api.example.com/v1
      models: [foo, bar, baz]

/model shows "acme (0)"; bypassing normalize in list_authenticated_providers
returns three models, confirming the drop happens in normalize.

Adds four unit tests covering list→dict conversion, dict pass-through,
filtering of empty/non-string entries, and the empty-list case.

hermes_cli/config.py

@@ -2055,6 +2055,14 @@ def _normalize_custom_provider_entry(
     models = entry.get("models")
     if isinstance(models, dict) and models:
         normalized["models"] = models
+    elif isinstance(models, list) and models:
+        # Hand-edited configs (and older Hermes versions) write ``models`` as
+        # a plain list of model ids. Preserve them by converting to the dict
+        # shape downstream code expects; otherwise normalize silently drops
+        # the list and /model shows the provider with (0) models.
+        normalized["models"] = {
+            str(m): {} for m in models if isinstance(m, str) and m.strip()
+        }
 
     context_length = entry.get("context_length")
     if isinstance(context_length, int) and context_length > 0: