fix(gateway): refresh cached agent max_iterations after per-turn config reload

[Zyrixtrex]

Summary

This fixes a gateway stale-state bug where agent.max_turns changes were not applied reliably on the next turn.

In the cached-agent path, the gateway could continue using an outdated max_iterations value even after the per-turn config/env reload completed.

Fixes #

Changes

• read HERMES_MAX_ITERATIONS after _reload_runtime_env_preserving_config_authority()
• refresh max_iterations when reusing a cached AIAgent
• add regression coverage for cached-turn budget refresh

Files

• gateway/run.py
• tests/gateway/test_agent_cache.py

Validation

Ran locally:

python -m pytest tests/gateway/test_agent_cache.py -q --timeout-method=thread
python -m pytest tests/gateway/test_runtime_env_reload_config_authority.py -q --timeout-method=thread

Passed:

tests/gateway/test_agent_cache.py
tests/gateway/test_runtime_env_reload_config_authority.py

[alt-glitch]

Related to merged #21240 (preserve max_turns after env reload). This PR addresses a remaining edge case: the cached-agent path where max_iterations isn't refreshed after per-turn config reload, even though the env reload itself was fixed. Also related to open #17306 and #18230.

[kshitijk4poor]

Closing as already resolved on current main.

This PR's specific fix — refreshing a reused cached agent's max_iterations from current config each turn — is already implemented in the cached-agent reuse path of gateway/run.py:

self._init_cached_agent_for_turn(agent, _interrupt_depth)
# Refresh agent max_iterations from current config
# (cached agent may have been created with old config)
agent.max_iterations = max_iterations

where max_iterations comes from _current_max_iterations() (which reloads runtime env while preserving config.yaml's agent.max_turns). So a cached agent no longer keeps a stale budget after a config/env reload. Thanks for catching and documenting the cached-turn staleness.