Add Hermes Agent and OpenClaw gateway integration docs

Add mention-gate security note and fix MCP startup

Add mention-gate cross-reference for group chat users

Rewrite Why section with contractor/supplier use case

Remove migration section

Add GPL-3.0 license and security policy

Add Why section with use cases and real-world example

Rewrite README for new users

Fix E2EE decryption: use room.messages() instead of raw HTTP API

Remove install methods that don't exist yet

Fix README mismatches found in doc audit

Fix all audit findings — E2EE decrypt, security, MCP errors

Initial release — E2EE Matrix bridge in Rust