v0.5.1 — CLI + MCP parity for live print-parameter adjust

Added

• CLI parity with the new live-adjust API. Three new top-level
  commands matching the library and HTTP surfaces shipped in 0.5.0:
  • centauri speed <silent|balanced|sport|ludicrous|50|100|130|160>
  • centauri fan [--model N] [--aux N] [--chamber N]
  • centauri temp [--nozzle N] [--bed N] [--chamber N]
    All require --enable-control and accept any subset of fan/heater
    flags (omitted axes are left untouched).
• MCP tool parity: three new tools (only registered with
  --enable-control) — set_print_speed, set_fan_speed,
  set_temperatures. Same shapes as the HTTP endpoints; not marked
  "DESTRUCTIVE" because live runtime adjustment is their entire
  purpose.

Fixed

• 0.5.0 shipped the live-adjust API to the library, HTTP server, and
  web UI but missed the CLI and MCP server. This release closes that
  parity gap — every surface now exposes the same control set.