Major refactor for quality and cleanup

[thevictorlopez]

Type System & Spec Alignment

• Aligned XARFEvidence and EvidenceSource enums to match actual spec values
• Fixed hallucinated types; added missing types for nested objects (MessageInfo, swarm_info, etc.)
• Removed SeverityLevel enum; fixed content_type injection in v3 Content reports
• Made swarm_info required per spec

Public API (Parser / Generator / Validator) Refactor

• Major refactor of Generator, Parser, and Validator to simplify codebase and remove type duplication
• Fixed strict mode to work correctly with x-recommended properties
• Evidence size calculated automatically on report generation
• Replaced UUID generation with a sane method
• Delegated schema lookup (category/types) to SchemaRegistry
• Fixed collectMissingOptionalFields to follow $ref references
• Several fixes to V3 → V4 Compatibility Layer
• Barrel exports cleaned up
• Removed sample generation helpers
• Removed dead code and conditions
• Removed unnecessary content_type top-level injection

Test Suite

• Major test suite update alongside public API cleanup
• Removed validator.edge-cases.test.ts (334 lines deleted)
• Significantly expanded validator.test.ts and v3-legacy.test.ts

Documentation / Misc.

• Cleaned up outdated docs; bumped spec version to 4.2.0
• Updated email address; bumped dependencies
• Removed stale Claude-generated artifacts