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>

languages/en-GB/westgate.json

@@ -20,5 +20,8 @@
     "footer.how-to-join": "How to Join",
     "footer.copyright": "© %1 Shadows Over Westgate · A NWN:EE Persistent World",
     "footer.setting": "Forgotten Realms · Westgate · Sea of Fallen Stars",
-    "footer.powered-by": "Powered by"
+    "footer.powered-by": "Powered by",
+    "support-inbox.title": "Support inbox",
+    "support-inbox.empty": "Nothing new",
+    "support-inbox.view-all": "Go to Support"
 }