feat(feed): move sort + view into the chip row with responsive overflow

Sort and the view switcher are tightly bound to the grid, so pin them to the
right of the applied-filter row (directly above the cards) instead of the filter
toolbar; they render there on both the feed and channel-scoped views.

ActiveFilterChips now shares that row with the controls and trims itself so it
never crowds them, measuring fit off a hidden mirror of the full chip set:
- wide  -> show as many chips as fit, then a "+N" pill whose popover holds the rest;
- narrow -> collapse every chip into one "N filters" pill whose popover holds them all.
Both popovers list the (overflowed / all) chips, each removable, plus Clear all.

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

@@ -3,6 +3,8 @@
     "label": "Filtered by",
     "remove": "Remove filter: {{name}}",
     "contentNone": "No content types",
+    "count_one": "{{count}} filter",
+    "count_other": "{{count}} filters",
     "maxAge_one": "Last {{count}} day",
     "maxAge_other": "Last {{count}} days"
   },

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

@@ -3,6 +3,8 @@
     "label": "Szűrve",
     "remove": "Szűrő eltávolítása: {{name}}",
     "contentNone": "Nincs tartalomtípus",
+    "count_one": "{{count}} szűrő",
+    "count_other": "{{count}} szűrő",
     "maxAge_one": "Utolsó {{count}} nap",
     "maxAge_other": "Utolsó {{count}} nap"
   },