v0.5.5-GuppyKE

Changed

• WiFi power-save toggle renamed "Low Latency" and expanded into a full bundle — it now disables WiFi
  power-save, turns off background roam-scans, and stops Bluetooth (the BCM4343 shares one antenna for
  WiFi/BT, and the coexistence caused latency spikes).

Added

• TMC Autotune user guide — explains the greyed-out Save button, documents all four tuning goals,
  and notes the Sensorless Threshold is hidden on the KE.

Fixed

• WiFi "Low Latency" hint left-aligned and shrunk (montserrat 14→12) so it clears the Back button.
• Broken Skew documentation link; completed the README documentation index.