fix: provider/model resolution — salvage 4 PRs + MiniMax aux URL fix (#5983)

Salvaged fixes from community PRs:

- fix(model_switch): _read_auth_store → _load_auth_store + fix auth store
  key lookup (was checking top-level dict instead of store['providers']).
  OAuth providers now correctly detected in /model picker.
  Cherry-picked from PR #5911 by Xule Lin (linxule).

- fix(ollama): pass num_ctx to override 2048 default context window.
  Ollama defaults to 2048 context regardless of model capabilities. Now
  auto-detects from /api/show metadata and injects num_ctx into every
  request. Config override via model.ollama_num_ctx. Fixes #2708.
  Cherry-picked from PR #5929 by kshitij (kshitijk4poor).

- fix(aux): normalize provider aliases for vision/auxiliary routing.
  Adds _normalize_aux_provider() with 17 aliases (google→gemini,
  claude→anthropic, glm→zai, etc). Fixes vision routing failure when
  provider is set to 'google' instead of 'gemini'.
  Cherry-picked from PR #5793 by e11i (Elizabeth1979).

- fix(aux): rewrite MiniMax /anthropic base URLs to /v1 for OpenAI SDK.
  MiniMax's inference_base_url ends in /anthropic (Anthropic Messages API),
  but auxiliary client uses OpenAI SDK which appends /chat/completions →
  404 at /anthropic/chat/completions. Generic _to_openai_base_url() helper
  rewrites terminal /anthropic to /v1 for OpenAI-compatible endpoint.
  Inspired by PR #5786 by Lempkey.

Added debug logging to silent exception blocks across all fixes.

Co-authored-by: Hermes Agent <hermes@nousresearch.com>

hermes_cli/model_switch.py

@@ -791,12 +791,12 @@ def list_authenticated_providers(
         if overlay.auth_type in ("oauth_device_code", "oauth_external", "external_process"):
             # These use auth stores, not env vars — check for auth.json entries
             try:
-                from hermes_cli.auth import _read_auth_store
-                store = _read_auth_store()
-                if store and pid in store:
+                from hermes_cli.auth import _load_auth_store
+                store = _load_auth_store()
+                if store and (pid in store.get("providers", {}) or pid in store.get("credential_pool", {})):
                     has_creds = True
-            except Exception:
-                pass
+            except Exception as exc:
+                logger.debug("Auth store check failed for %s: %s", pid, exc)
         if not has_creds:
             continue