Refresh project README and adopt Apache 2.0

[gbaudrit-codex]

Summary

• refresh the README around Agentstration as an open-source, self-hosted control plane
• reflect current Management, Runtime, Work and Flow capabilities
• include recent Trigger, LocalAI, llama.cpp, AEP, governed Tool execution, durable interaction, Pack and identity work
• make Managed with a local model provider the normal local path and describe Deterministic as a test/diagnostic fallback
• add the public website and published documentation portal
• correct the clone URL to gbaudrit/agentstration
• adopt the Apache License 2.0 for Agentstration and the autonomous AEP subtree
• add Agentstration and AEP NOTICE files, contribution terms and Apache-2.0 package metadata
• include LICENSE and NOTICE in packable .NET artifacts

Verification

• reviewed main, the latest 30 commits and the detailed current-capabilities, architecture, Pack and model-provider documentation
• verified all newly introduced public website and documentation URLs return HTTP 200
• used the official unmodified Apache License 2.0 text from apache.org for both license files
• verified AEP and root package metadata use the SPDX expression Apache-2.0
• documentation, licensing and package-metadata changes only; no product behavior changed