fix: cleanup Qwen OAuth provider gaps

- Add HERMES_QWEN_BASE_URL to OPTIONAL_ENV_VARS in config.py (was missing
  despite being referenced in code)
- Remove redundant qwen-oauth entry from _API_KEY_PROVIDER_AUX_MODELS
  (non-aggregator providers use their main model for aux tasks automatically)

hermes_cli/config.py

@@ -724,6 +724,14 @@ OPTIONAL_ENV_VARS = {
         "category": "provider",
         "advanced": True,
     },
+    "HERMES_QWEN_BASE_URL": {
+        "description": "Qwen Portal base URL override (default: https://portal.qwen.ai/v1)",
+        "prompt": "Qwen Portal base URL (leave empty for default)",
+        "url": None,
+        "password": False,
+        "category": "provider",
+        "advanced": True,
+    },
     "OPENCODE_ZEN_API_KEY": {
         "description": "OpenCode Zen API key (pay-as-you-go access to curated models)",
         "prompt": "OpenCode Zen API key",