fixup: drop state_keys= call, bump langgraph branch pin
Paired langgraph PR no longer takes state_keys — ToolNode now reads the
full channel state via CONFIG_KEY_READ internally. Revert create_agent's
factory to its original state schema resolution location and drop the
state_keys argument.
Lockfile updated to the latest commit on sr/tool-call-no-state-inline.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
