Eliminates the JS<->Python drift bug class by making one Python function
the source of truth for state -> configs_json. Both the runtime
(generate_config) and the new preview endpoint (next commit) call it.
Adds golden test for the lora-strength-arrays bracket case that just
broke (regression guard).
Also loads the real config_builder_node module in conftest.py (instead
of a bare stub) so that tests against UltimateConfigBuilder methods work
correctly. Stubs network_utils before loading to satisfy the relative
import.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
