feat(feed): 1D — content-type chips + sort in a toolbar above the cards

Move content type and ordering out of the filter sidebar into a feed toolbar (approved
proposal 2): a prominent content-type chip row (Normal/Shorts/Live toggle chips) with the
sort control + count + reshuffle in a quieter row beneath it. The toolbar renders even on
'no matches' so content-type can be turned back on after it filtered everything out. The
sidebar keeps Show / Upload date / Language / Topic; 'sort' and 'content' widgets removed
from the layout (normalizeLayout drops them from any saved layout). New feed.sortLabel
string (HU/EN/DE).

frontend/src/i18n/locales/en/feed.json

@@ -8,6 +8,7 @@
   "noMatches": "No videos match these filters.",
   "videoCount_one": "{{formattedCount}} video",
   "videoCount_other": "{{formattedCount}} videos",
+  "sortLabel": "Sort",
   "loadingMore": "Loading more…",
   "hiddenNamed": "Hidden “{{title}}”",
   "hidden": "Video hidden",