The legacy online simulation path still exported internal ACTIVE states as STATUS keywords, which EPANET 2 rejects. Preserve numeric settings and EPANET 3 output while passing the format through both exporters. Surface the original engine error inside the model transaction so failed runs roll back before result storage.
Regression guard: six failures reproduced on the deployed baseline, including native input validation. All 34 focused export, service and endpoint checks pass after the fix; the real project also returns native node and link results.
Reorganize WNDB by responsibility and remove legacy scheme endpoints.\n\nRoute analysis and time-series access through project pools, preserve transactional realtime replacement, and refresh GIS materialized views after writes.\n\nAdd database architecture documentation, live pooling coverage, API contract updates, and executable container verification.\n\nBREAKING CHANGE: legacy scheme APIs and flat app.native.wndb module imports are removed.
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