Obligation-First v0.2.2-draft

Security hardening release package for the v0.2 draft line. v0.1 adopter records remain valid without schema migration.

• manifest.json - machine-readable release package manifest
• sha256.txt - SHA-256 checksum index
• RELEASE_NOTES-v0.2.2-draft.md - release notes and verification summary
• /v1/context.jsonld - JSON-LD context
• /v1/schema/ - JSON Schemas
• /.well-known/assistant-guide.txt - GuideCheck assistant guide