Enhance README with detailed BotBook information

Add BotBook runtime OS overview doc

BotBook v0.3 — add DAG workflow engine, run registry, and control plane runtime

BotBook v0.2 — multi-agent workflows, CLI lifecycle commands, and runtime modules

BotBook v0.1 — CLI agent runtime with Grok integration, memory, and agent scaffolding

add agent DNS, capability registry, event bus, and federated node registry

add distributed job scheduler, worker runtime, and agent contract economy

agent contract + escrow layer

ignore runtime audit logs

Agent RPC + Illuu execution + PrivateVault governance + tool runtime

integrate LORK and PrivateVault adapters

add trust graph, contracts, payments, sharding layers

Revise README for improved clarity and branding

Remove flowchart from README.md

Fix README Mermaid rendering