Add missing summary_length and source_extraction_window fields to all
settings JSON payloads in api_settings_test.rs. The pipeline_test.rs,
generation-live.spec.ts, and api_syntheses_test.rs already had correct
fixtures or use JSON literals that are unaffected by the optional date field.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>