Make the support drawer core's notification drawer (sow-nodebb-plugin-support#10)

The first version of this drawer built its own rows in JS. This one renders
core's `partials/notifications_list` partial with entries the support plugin
now returns in core's notification shape, so the markup is literally the
notification drawer's: avatar block, stretched link, muted timeago, per-entry
read dot, All/Unread filter row, and the same two footer buttons. The
handlers mirror core's too — only the API paths differ, because the list is
plugin-owned (core's unread count is one aggregate with no hook to carve a
type out of it).

Opening the box no longer marks everything read: like the bell, an entry is
read when you click it or use "Mark all read", and the dot toggles both ways.

Deletes the bespoke row builder and its hand-rolled relative-time helper;
`$.timeago` is what core uses for JS-inserted rows. The dropdown reuses the
`.notifications-dropdown` class this theme already styles, so it needs no CSS
of its own. Hardcoded English is gone (the code-review finding on the first
version): every string is a translation key.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scss/westgate/_topbar.scss

@@ -173,8 +173,7 @@ $wg-topbar-panel-bg: rgba(21, 17, 26, 0.98);
 .wg-topbar .notifications-dropdown,
 .wg-topbar .chats-dropdown,
 .wg-topbar .drafts-dropdown,
-.wg-topbar .unread-dropdown,
-.wg-topbar .support-dropdown {
+.wg-topbar .unread-dropdown {
   width: min(24rem, calc(100vw - 1.5rem));
 }
 
@@ -190,10 +189,6 @@ $wg-topbar-panel-bg: rgba(21, 17, 26, 0.98);
   opacity: 0.7;
 }
 
-.wg-topbar .wg-support-item--unread {
-  font-weight: 600;
-}
-
 .wg-topbar .dropdown-item,
 .wg-topbar .btn.btn-ghost,
 .wg-topbar .btn.btn-light {