Document explicit business rules and domain primitives

[hnordt]

Summary

• add Draft 0009 for explicit, reusable business-rule descriptors and decision queries
• add Draft 0010 for explicit domain primitives, single-responsibility composition, and declared effects
• make the matching README and AGENTS invariants canonical

Why

Hyperkernel needs a stated architectural direction for AI- and developer-authored domain behavior: domain concepts must be explicit, composable contracts rather than rules hidden in arbitrary helpers or orchestration code.

AI usage

• Tool: Codex
• Work assisted by AI: planning and documentation
• AI usage level: supervised
• Change classification: Kernel, Extension

The author reviewed and directed the architectural decisions and wording.

Verification

• git diff --check
• npx prettier --check README.md AGENTS.md docs/design/README.md docs/design/0010-explicit-domain-primitives.md

Unresolved uncertainty

• Both design records are Drafts; they do not introduce implemented public APIs.
• Effect delivery and a value-derivation primitive remain separate future contracts.
• A code-first API can enforce purity by capability and declared structure, but TypeScript alone cannot prove semantic purity of arbitrary callbacks.