mx — Rust CLI for memory graph and KV store operations.

Used by hearth and companions to persist memory, traits, and session state to a SurrealDB backend. Companions invoke it via the hearth mx proxy, which injects credentials at runtime. No runbook yet — the codebase is the reference.

Key commands: memory add, memory list, memory get, kv set, kv get. The --mine flag scopes queries to the calling agent (MX_CURRENT_AGENT).

If you change behavior of existing commands, note it in the CHANGELOG and verify companion-facing usage in ~/.soren/config/agents/ still holds.