Root cause: layers.id is TEXT PRIMARY KEY (global unique across all drawings).
Hardcoded IDs layer-0..layer-4 collided when multiple projects tried to create
the same layer IDs. Second project got UNIQUE constraint failed on POST /layers.
Without layers, elements had dangling layer_id refs causing FOREIGN KEY errors.
Fix: makeInitialLayers() generates unique IDs: layer-{timestamp}-{index}.
activeLayerId initialized from first layer, not hardcoded.
activeLayerName uses activeLayerId variable, not hardcoded layer-0.
On project load with existing layers, activeLayerId set from first DB layer.
Leopoldadmin
39422a4348