Add jqwik property-based testing for JTD validation

[simbo1905]

Summary

• add into module JtdPropertyTest property-based integration test that exercises exhaustive schema/document permutations
• implement sealed-schema generators, compliant document builders, and negative case creation with JUL logging for traceability
• register a jqwik ArbitraryProvider to drive exhaustive GenerationMode coverage

Testing

• ./mvnw -pl json-java21-jtd verify -Djava.util.logging.ConsoleHandler.level=INFO

Implementation Details

• Add jqwik dependency to json-java21-jtd module
• Create JtdPropertyTest class with property-based tests
• Implement custom ArbitraryProvider for JTD schema generation
• Create generators for all 8 JTD schema forms (Empty, Ref, Type, Enum, Elements, Properties, Values, Discriminator)
• Build compliant JSON document generators for each schema type
• Implement negative case generation to test validation failures
• Add comprehensive JUL logging for test traceability
• Ensure exhaustive GenerationMode coverage for thorough testing

Acceptance Criteria

• Property-based tests run successfully with jqwik
• All 8 JTD schema forms are covered by generators
• Both positive and negative test cases are generated
• JUL logging provides clear traceability of test execution
• Tests integrate with existing maven build process