Renamed trend_change_in_minutes → next_price_trend_change_in to align
with its sibling sensor next_price_trend_change (timestamp variant).
Follows the established best/peak price naming pattern where related
sensors share a common prefix (e.g. best_price_next_start_time /
best_price_next_in_minutes).
Updated entity key, translation key, friendly names (all 5 languages),
custom translations, coordinator constants, attribute routing, and
cache-clear mapping.
BREAKING CHANGE: Entity ID changes from
sensor.<home>_trend_change_in_minutes to
sensor.<home>_next_price_trend_change_in. Automations and dashboards
referencing the old entity ID must be updated.
Impact: Users with automations or dashboard cards referencing the old
sensor name need to update references. The sensor retains identical
functionality and attributes.