Ether 0.2.55

This release completes Plex migration watch-state folding for history-only
titles, removes the 100-item preview truncation in the admin console, and skips
empty Plex collections during import.

Plex Migration and Watch State

• Fold history-only plays into watched state and preview items: historical
  viewings resolved from /status/sessions/history/all for movies and episodes
  that were later removed or replaced in the source Plex library are now folded
  into the migration plan's watch records (plan.items) and upserted into
  state_watch (view_count, counted, and last_viewed_at) during import so
  every historical watch marks the title watched across Plex clients and
  recommendations (#152).
• Show all matched watch records in the import preview: removed the
  100-item display slice (plan.items.slice(0, 100)) in the Settings →
  Backups & import review list so the scrollable preview shows all matched
  watch records (#152).
• Skip and clean up empty Plex collections: collections and playlists in
  Plex with zero resolved titles (such as empty collection shells left behind
  after library files were removed) are no longer imported as empty titles
  specs that log invalid collection: sources[0].keys: pick at least one title
  on refresh, and any previously imported zero-title collection specs are
  automatically pruned by the collection scheduler (#152).