fix: do not build phantom Custom group when active provider is set (#206)

* fix: do not build phantom "Custom" group when active provider is set

When model.provider is a real provider (e.g. openai-codex) and model.base_url
is configured, hermes_cli reports 'custom' as an authenticated provider. The
WebUI model picker was building a separate "Custom" group for it and parking
the configured default_model there instead of under the active provider's
group — diverging from the TUI which correctly shows the model under its
configured provider.

Two fixes in api/config.py get_available_models():

1. Discard 'custom' from detected_providers when active_provider is set and
   isn't 'custom' itself. The base_url belongs to the active provider.

2. Replace the substring-based default-model injection check with an exact
   match against _PROVIDER_DISPLAY. The old check `active_provider.lower() in
   g.get('provider', '').lower()` silently failed for hyphenated IDs like
   'openai-codex' vs display name 'OpenAI Codex' (hyphen vs. space),
   falling through to groups[0] and landing the model in the alphabetical
   first group instead.

Adds two regression tests in tests/test_model_resolver.py covering both
conditions.

* fix: do not build phantom Custom group when active provider is set

Two bugs in get_available_models():

1. Phantom Custom group: hermes_cli reports 'custom' as authenticated
whenever model.base_url is set. With provider=openai-codex + base_url,
detected_providers contained both 'openai-codex' and 'custom', producing
a duplicate group. Fixed by discarding 'custom' from detected_providers
when the active provider is any real named provider.

2. Hyphen/space mismatch in default_model injection: the substring check
'openai-codex' in 'openai codex' is False (hyphen vs space), causing the
default model to fall through to groups[0] (alphabetically first provider)
instead of the active provider group. Fixed by using _PROVIDER_DISPLAY
for exact display-name comparison.

Also fixes test helper _available_models_with_full_cfg to clear model env
vars during the call, preventing real hermes profile env from leaking into
the test assertions.

---------

Co-authored-by: mbac <marco.baciarello@gmail.com>
Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

api/config.py

@@ -680,6 +680,14 @@ def get_available_models() -> dict:
                 _seen_custom_ids.add(_cp_model)
                 detected_providers.add('custom')
 
+    # If the user configured a real model.provider, the base_url belongs to
+    # THAT provider, not to a separate "Custom" group. hermes_cli reports
+    # 'custom' as authenticated whenever base_url is set, which would otherwise
+    # build a phantom "Custom" bucket next to the real provider's group. Drop
+    # it unless the user explicitly chose 'custom' as their active provider.
+    if active_provider and active_provider != 'custom':
+        detected_providers.discard('custom')
+
     # 5. Build model groups
     if detected_providers:
         for pid in sorted(detected_providers):
@@ -741,11 +749,21 @@ def get_available_models() -> dict:
         _norm = lambda mid: mid.split('/', 1)[-1] if '/' in mid else mid
         all_ids_norm = {_norm(m['id']) for g in groups for m in g.get('models', [])}
         if _norm(default_model) not in all_ids_norm:
-            # Determine which group to inject into
+            # Determine which group to inject into. Compare against the
+            # provider's display name from _PROVIDER_DISPLAY rather than
+            # doing a substring match on active_provider — substring
+            # matching breaks on hyphenated provider IDs like 'openai-codex'
+            # vs display name 'OpenAI Codex' (hyphen vs. space), which
+            # silently falls through to groups[0] and lands the model in
+            # the wrong group.
             label = default_model.split('/')[-1] if '/' in default_model else default_model
+            target_display = (
+                _PROVIDER_DISPLAY.get(active_provider, active_provider or '').lower()
+                if active_provider else ''
+            )
             injected = False
             for g in groups:
-                if active_provider and active_provider.lower() in g.get('provider', '').lower():
+                if target_display and g.get('provider', '').lower() == target_display:
                     g['models'].insert(0, {'id': default_model, 'label': label})
                     injected = True
                     break