[Future] Movement retrieval MCP tools (motion.search, motion.find_for_beat, motion.compose_phrase)

[HomenShum]

Observed during: Tragedy Practice Mode planning (2026-07-17).
Why it matters: Exposes the Motion Catalog to NodeAgent/Eve as typed MCP tools so an agent can compose phrases for a beat/genre/energy query.
Why out of scope: Depends on the Motion Catalog schema issue; P0 has no catalog.
Risk: B.