Obligation-First v0.5.0

Adds the of:ObligationCategory layer for jurisdiction-neutral duty concepts, extends of:anchors to reference them, and lets adopter naming profiles declare a version range so additive releases stop being lockstep flag days. Additive; v0.4.x records and profiles stay valid.

• manifest.json - machine-readable release package manifest
• sha256.txt - SHA-256 checksum index
• RELEASE_NOTES-v0.5.0.md - release notes and verification summary
• /v1/context.jsonld - JSON-LD context
• /v1/schema/ - JSON Schemas
• /.well-known/assistant-guide.txt - GuideCheck assistant guide

Full changelog