Expanded the root README to include the complete setup instructions
(crates table + intro + the full 7-section deployment guide that
previously lived only in docs/deployment.md, with the doc-link paths
adjusted for a root-level README and a list of every v2/v3 feature
plus the RF entry-relay scenario). docs/deployment.md is preserved for
in-tree navigation.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>