The default Behave `parse` matcher requires `{url}` to match at least
one character, so the `is_postgresql_url returns False for empty
string` scenario (langgraph_platform_remote_graph.feature:193) raised
an undefined-step error rather than exercising the function. Switch
just this step to the `re` matcher so `""` matches; the implementation
already handles empty input correctly.
ISSUES CLOSED: #10792
Split the 573-line langgraph_platform_remote_graph_steps.py into three focused files (remote_graph_config_steps.py, remote_graph_manager_steps.py, postgresql_config_steps.py) to comply with the 500-line file limit.
Also removes the unwanted repo subproject entry (merge artifact).
HAL9000