v0.5.1 — Hide rain-start/-end tiles when irrelevant

v0.5.1 — Hide rain-start/-end tiles when irrelevant

Fixed

• The 'Regen ab' tile no longer shows 'Unbekannt' while it's already
  raining — it's hidden via a visibility condition (raining = off).
  Symmetric treatment for 'Regen endet' (visible only when raining =
  on). Cleaner than chasing sentinel values in the sensor itself.