PDD converter maps OnDelete/OnUpdate code 0 to NO ACTION instead of RESTRICT

[DirectDuck]

Version: 0.0.3

pgdesigner convert produces semantically incorrect FK actions when importing MicroOLAP pgDesigner .pdd files. The numeric action codes stored in PDD are decoded using the wrong mapping — specifically, codes 0 and 3 appear to be swapped relative to what MicroOLAP's own SQL generator emits.

Steps to reproduce:

1. Take any .pdd file containing <REFERENCE ... OnDelete="0" OnUpdate="0">
2. Run pgdesigner convert schema.pdd -o schema.pgd
3. Run pgdesigner generate schema.pgd -o schema.sql
4. Inspect the generated ALTER TABLE ... ADD CONSTRAINT ... FOREIGN KEY statements