Apply pending changes from the banner

An Apply now button on the pending-changes banner applies the draft and
stays on the page; if the changes are refused, a dialog says why.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -46,6 +46,9 @@ All notable changes to Jarl are documented here. The format follows
   indents and Enter keeps the indentation (Esc, then Tab, moves on). With
   a draft open, the tables show the draft's values, so a staged edit stays
   visible after Save.
+- The pending-changes banner has an Apply now button: it applies your
+  draft without going to the Changes page, and stays on the page you're
+  on. If the changes are refused, a dialog says why and links to Changes.
 - Blocking page: blocklists and rules have an Edit button (name, URL,
   views, comment; a rule's action and scope). The list button that
   downloads now is called Refresh, like `jarl blocklist refresh`.