* Add support for known PostgreSQL types and modifiers
* Implement canonicalization for PostgreSQL types
* Introduce unit tests for PostgreSQL type handling
* Introduced GUID field to Database, Domain, DomainTable, Schema, Table, View, Sequence, Column, Index, Relationship, Constraint, Enum, and Script models.
* Updated initialization functions to assign new GUIDs using uuid package.
* Enhanced DCTX reader and writer to utilize GUIDs from models where available.
