actop 1.2.2

Added

• Fan RPM via SMC (docs/TODO-architecture-roadmap.md Tier-1 item): smc.py
  discovers per-fan actual-RPM keys (F{n}Ac, flt type, count from FNum)
  alongside the existing temperature-key discovery, and SMCReader gains
  read_fan_rpms() / fan_available. Threaded through SampleResult →
  SystemSnapshot.fan_rpms / fan_available (public API and NDJSON/Prometheus
  export), and a new TUI "Fan" row that hides entirely on fanless Macs
  (mirrors the bandwidth_available hide-row pattern) instead of showing a
  phantom 0 RPM.