Hermes CI triage

CI is currently failing for this PR in two places:

1. tests/agent/test_agent_init.py::{test_init_agent_rejects_model_below_user_config_override,test_init_agent_rejects_model_below_minimum_without_override} fail because the lightweight SimpleNamespace test double is missing agent._is_direct_openai_url. Add it in make_agent() alongside _is_azure_openai_url.

2. tests/run_agent/test_plugin_context_engine_init.py::test_plugin_engine_update_model_args now raises for openrouter/auto when detected context length is 0. The previous guard was if _ctx and _ctx < MINIMUM_CONTEXT_LENGTH, so unknown/undetectable context (0) did not fail startup. The new minimum check should likely preserve that behavior, e.g. only enforce when _ctx is truthy/known:

if _config_context_length is not None and _ctx and _ctx < _config_context_length:
    ...
if _config_context_length is None and _ctx and _ctx < MINIMUM_CONTEXT_LENGTH:
    ...

Also small style nit: if( should be if ( / preferably no extra parens, and the raise ValueError(...) closing paren is over-indented.

Evidence: failing jobs test (2) and test (3) in workflow run 26838174166.

The split logic removes the _ctx and guard that the original code relied on to skip the check when context length is unknown (0).

Original code (line 1476 on main):

_ctx = getattr(agent.context_compressor, "context_length", 0)
if _ctx and _ctx < MINIMUM_CONTEXT_LENGTH:

The _ctx and short-circuit means: "if the compressor couldn't determine context length (0), skip the check entirely."

PR code:

if(_config_context_length is not None and _ctx < _config_context_length):

When _ctx is 0 (unknown) and model.context_length is configured (e.g., 60000), this evaluates to True and 0 < 60000 → True, raising a spurious ValueError. The same problem applies to the second condition: 0 < MINIMUM_CONTEXT_LENGTH would also be True.

Suggested fix — restore the _ctx truthiness check on both branches:

if _ctx and _config_context_length is not None and _ctx < _config_context_length:
    raise ValueError(...)
if _ctx and _config_context_length is None and _ctx < MINIMUM_CONTEXT_LENGTH:
    raise ValueError(...)

This preserves the original "skip when unknown" behavior while adding the user-configured override path. A test for the _ctx == 0 case would also be valuable.