fix(header): show the sync chip only where it means something, trim its copy

The chip is about YouTube subscription syncing, so it only earns its place on
the feed those subscriptions fill and the manager where you curate them. On
Plex — a different source entirely — plus playlists, downloads and stats it was
just noise.

Its tooltips were written for a roomy sidebar block and read like documentation
on a pill: the counts explanation went 120 chars -> 48, the full-history one
142 -> 46, and pause/resume drop "background".

frontend/src/components/Header.tsx

@@ -120,8 +120,12 @@ export default function Header({
       />
       {search}
       {/* Per-user sync status — it used to cost the nav rail a whole block. It sits with the other
-          pills rather than pinned to the far right: on a wide window that just strands it. */}
-      <SyncStatus isAdmin={me.role === "admin"} onGoToFullHistory={onGoToFullHistory} />
+          pills rather than pinned to the far right: on a wide window that just strands it. Only on
+          the two modules it says anything about: the feed those subscriptions fill, and the manager
+          where you curate them. It's noise on Plex (a different source entirely), playlists, etc. */}
+      {(page === "feed" || page === "channels") && (
+        <SyncStatus isAdmin={me.role === "admin"} onGoToFullHistory={onGoToFullHistory} />
+      )}
     </div>
   );
 }

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

@@ -39,7 +39,7 @@
   "sync": {
     "yours": "yours",
     "total": "total",
-    "countTooltip": "Videos from your subscriptions, against the total in the shared catalog that every user's subscriptions have pulled in.",
+    "countTooltip": "Your subscriptions vs. the whole shared catalog.",
     "paused": "paused",
     "syncing": "{{count}} syncing",
     "backfillingHistory": "fetching history",
@@ -47,9 +47,9 @@
     "recentQueued": "{{count}} queued",
     "allSynced": "all synced",
     "withoutFullHistory": "{{count}} without full history",
-    "fullHistoryTooltip": "Some of your channels only have their recent uploads. Click to open the channel manager (filtered to these) and request their full back-catalog.",
-    "pause": "Pause background sync",
-    "resume": "Resume background sync"
+    "fullHistoryTooltip": "Recent uploads only — click to fetch the rest.",
+    "pause": "Pause sync",
+    "resume": "Resume sync"
   },
   "banner": {
     "updated": "Updated to v{{version}} — see what's changed.",

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

@@ -39,7 +39,7 @@
   "sync": {
     "yours": "tiéd",
     "total": "összes",
-    "countTooltip": "A feliratkozásaidból származó videók száma a megosztott katalógus teljes számához képest, amelyet az összes felhasználó feliratkozásai gyűjtöttek össze.",
+    "countTooltip": "A feliratkozásaid a teljes megosztott katalógushoz képest.",
     "paused": "szüneteltetve",
     "syncing": "{{count}} szinkronizálás alatt",
     "backfillingHistory": "előzmény letöltése",
@@ -47,9 +47,9 @@
     "recentQueued": "{{count}} sorban",
     "allSynced": "minden szinkronban",
     "withoutFullHistory": "{{count}} teljes előzmény nélkül",
-    "fullHistoryTooltip": "Néhány csatornádnak csak a legutóbbi feltöltései vannak meg. Kattints a csatornakezelő megnyitásához (ezekre szűrve), és kérd le a teljes archívumukat.",
-    "pause": "Háttér-szinkronizálás szüneteltetése",
-    "resume": "Háttér-szinkronizálás folytatása"
+    "fullHistoryTooltip": "Csak a legutóbbi feltöltések — kattints a többiért.",
+    "pause": "Szinkron szüneteltetése",
+    "resume": "Szinkron folytatása"
   },
   "banner": {
     "updated": "Frissítve a(z) v{{version}} verzióra — nézd meg, mi változott.",