fix: Ollama Cloud auth, /model switch persistence, and alias tab completion

- Add OLLAMA_API_KEY to credential resolution chain for ollama.com endpoints
- Update requested_provider/_explicit_api_key/_explicit_base_url after /model
  switch so _ensure_runtime_credentials() doesn't revert the switch
- Pass base_url/api_key from fallback config to resolve_provider_client()
- Add DirectAlias system: user-configurable model_aliases in config.yaml
  checked before catalog resolution, with reverse lookup by model ID
- Add /model tab completion showing aliases with provider metadata

Co-authored-by: LucidPaths <LucidPaths@users.noreply.github.com>

hermes_cli/runtime_provider.py

@@ -377,9 +377,13 @@ def _resolve_openrouter_runtime(
         ]
     else:
         # Custom endpoint: use api_key from config when using config base_url (#1760).
+        # When the endpoint is Ollama Cloud, check OLLAMA_API_KEY — it's
+        # the canonical env var for ollama.com authentication.
+        _is_ollama_url = "ollama.com" in base_url.lower()
         api_key_candidates = [
             explicit_api_key,
             (cfg_api_key if use_config_base_url else ""),
+            (os.getenv("OLLAMA_API_KEY") if _is_ollama_url else ""),
             os.getenv("OPENAI_API_KEY"),
             os.getenv("OPENROUTER_API_KEY"),
         ]