Summary

Fixes #3410.

Two separate bugs that both affect custom OpenAI-compatible endpoint users.

Fix 1 — auxiliary_client: mirror active runtime in _resolve_custom_runtime

Root cause

_resolve_custom_runtime() hardcoded requested="custom" when calling
resolve_runtime_provider(). The problem: _get_named_custom_provider()
explicitly returns None when requested_norm == "custom" — it only matches
named entries like custom:local. So named custom providers saved in
config.yaml were silently bypassed.

The auxiliary path then fell through to env-var resolution
(OPENAI_BASE_URL / OPENAI_API_KEY), which can carry different credentials
or nothing at all — even though the main agent was already running successfully
against the named provider.

Fix

resolve_requested_provider()          # what provider is the main agent using?
  → "custom:local"                    # reads config.yaml / HERMES_INFERENCE_PROVIDER

resolve_runtime_provider(requested="custom:local")   # same path as main agent
  → { provider: "custom", source: "custom_provider:local", api_key: "...", ... }

If the active provider is not a custom endpoint (e.g. nous, openrouter),
fall back to requested="custom" so env-driven OPENAI_BASE_URL setups keep working.

Also adds DEBUG-level logging of the credential source selected for auxiliary
resolution.

Fix 2 — setup: reload config after _model_flow_custom to prevent clobber

Root cause

_model_flow_custom() writes model.provider and model.base_url to disk via
its own independent load_config() + save_config() cycle — it does not
mutate the outer config dict that run_setup_wizard() holds.

After _model_flow_custom returns, run_setup_wizard() calls save_config(config)
with the stale outer dict (no provider, no base_url), silently overwriting
the correct values.

Net effect: .env is right, config.yaml is wrong → the user must run
hermes model again to recover, and vision / auxiliary tooling also fails.

Fix

After _model_flow_custom() returns, reload the on-disk state back into the
outer config dict so the subsequent save_config(config) is a no-op:

config.clear()
config.update(load_config())

Changes

• agent/auxiliary_client.py — _resolve_custom_runtime(): use resolve_requested_provider() first
• hermes_cli/setup.py — run_setup_wizard(): reload config after custom flow
• tests/agent/test_auxiliary_client.py — 5 new tests + isolation fix
• tests/hermes_cli/test_setup_model_provider.py — regression test for config clobber

Tests

103 passed in test_auxiliary_client.py
1 passed  in test_setup_model_provider.py::test_custom_setup_wizard_persists_provider_in_config