refactor: rebrand userscript storage keys, hosts and wordmark

backend/internal/web/static/filter.js

@@ -46,7 +46,7 @@
 
   // htmx replaces the list on a tab switch, so re-apply to the new cards.
   document.body.addEventListener("htmx:afterSwap", applyFilter);
-  document.addEventListener("mangabm:refilter", applyFilter);
+  document.addEventListener("bmgr:refilter", applyFilter);
 })();
 
 function setActiveTab(el) {
@@ -58,7 +58,7 @@ function setActiveTab(el) {
   });
   // The strip is outside the swapped region, so its visibility is re-decided
   // here rather than by the server that just answered.
-  document.dispatchEvent(new Event("mangabm:refilter"));
+  document.dispatchEvent(new Event("bmgr:refilter"));
 }
 
 // The chapter-edit form and the archive/finish/remove confirm rows are the