v0.6.2 — Auto-install pysteps on HA OS

v0.6.2 — Auto-install pysteps on HA OS

Changed

• Selecting the pysteps engine now triggers an automatic dependency
  install via Home Assistant's async_process_requirements API.
  HA OS / Supervised / Container users no longer need shell access to
  pip install pysteps — picking the engine in the config flow is
  enough. First install takes 30–60 s on x86 (numpy + scipy + opencv
  wheels download). Subsequent restarts reuse the installed package.
  Falls back to the simple engine and logs a warning if the install
  fails (e.g. missing wheel for an unusual architecture).
• README and config-flow help text updated to reflect the new
  zero-shell install path.