feat(channels): R14 zoom-fit table — fluid columns + column fogyókúra

- DataTable: opt-in `fixedLayout` (colgroup + table-layout:fixed) so the
  table fits its container at any zoom/text-size; only the channel manager
  opts in — playlists/discovery/Plex keep auto-sizing.
- Remove the N/S/L and Sync columns from the manager table. Fully-synced
  status becomes a ✓ charm on the Stored count; the sync filter moves to an
  `applySyncFilter` pre-filter still driven by the top chips.
- Channel column is now fluid: ChannelLink truncates with the full name on
  hover (title). Data columns get fixed widths so only Channel/About flex.
- N/S/L (normal/short/live) breakdown moves to the channel page: add the
  three counts to the channelDetail endpoint (one grouped query, same
  filters as the list) + the ChannelDetail type + a meta-line entry.
- Drop the now-dead sync/types i18n keys (en+hu).

frontend/src/lib/api/channels.ts

@@ -27,6 +27,9 @@ export interface ChannelDetail {
   explored: boolean;
   blocked: boolean;
   stored_videos: number;
+  count_normal: number;
+  count_short: number;
+  count_live: number;
   deep_requested: boolean;
   priority: number;
   backfill_done: boolean;