fix(search): keep Load more; the count selector sets the batch size

Clarified per intent: the results-count selector controls how many results each fetch gathers,
and Load more pulls another batch of that size (restored). The infinite query already threads the
count into every page, so Load more honours the selected size. Added a tooltip on the selector.

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

@@ -53,6 +53,7 @@
     "ephemeralNote": "These results are temporary — they clear automatically unless you watch or save one.",
     "clearNow": "Clear now",
     "cleared_one": "Cleared {{count}} result",
-    "cleared_other": "Cleared {{count}} results"
+    "cleared_other": "Cleared {{count}} results",
+    "showHint": "How many results to fetch at a time — Load more pulls another batch of this size."
   }
 }