Derive a `source` bucket per collection from the already-synced title + smart
flag (no schema change, no re-sync): external list providers (IMDb/TMDb/TVDb/
Trakt) by leading token, Plex smart lists via the smart flag, everything else a
genuine "collection". Returned on each info-page collection strip so the client
can show/hide each type independently. Adds the stripSource labels (en/hu/de).