docs: position Hikmah as a deterministic agent kernel

[CodeWithJuber]

Summary

• lead with implemented Rust memory, provenance, audit, recall, planning and decision controls
• add recruiter-verifiable source and test links
• state the local reference-implementation boundary and unsupported GenAI/enterprise areas
• preserve setup, architecture and host-adapter guidance

Evidence boundary

Hikmah Stack is not presented as an LLM application, vector-RAG system, tool-calling runtime or production enterprise platform.

Validation

• replacement README checked against the audited default-branch tree
• Markdown structure and whitespace reviewed