v0.3.1

A repair to what the integration says, not to what it does. It already spoke
English and Italian, and the two files had been in step since the first release,
which is exactly why this went unseen: every check that looked at the
translations came back clean, and none of them could see the text that never
reached a translation file at all.

The warning of 0.1.0 and 0.3.0 still stands: the error budget is argued from soil
physics and not yet measured against a probe in the ground, and the placement
thresholds are argued rather than measured.

Fixed

• Nothing the user reads is written in Python any more. The integration
  already shipped in English and Italian, but three dropdowns and nine error
  messages were spelled out in the code and never reached a translation file, so
  an Italian install met them in English. The soil texture menu, the root depth
  unit and the rain gauge type now take their labels from the translations like
  everything else, and every refusal a service can answer with is a translated
  sentence rather than a literal. The rain gauge dropdown is the plainest case:
  it already carried a translation key and both translations, and an inline
  label passed next to them quietly won, so the menu offered event and
  accumulator in every language.
• services.yaml no longer repeats the name and description of each service and
  field. Home Assistant reads those from the translations, which means the copy
  in the YAML was a second English original that could drift from the translated
  one with nothing to catch it. The file now carries only what has no language:
  which fields exist, whether they are required, their selector and an example.
• pyproject.toml declared version 0.1.0 while the integration was at 0.3.0.
  The release pipeline reads the manifest and was never affected.

Added

• Four guards against the ways a translation goes missing without a sound, and a
  fifth widened from English to every language. A value a dropdown can show with
  no label, an error raised with no message, an entity whose name is absent,
  translatable text creeping back into services.yaml, and a referenced
  selector key missing from any of the languages. They parse the modules rather
  than importing them, so they run in the environment that has no Home
  Assistant.