Show the publication after the feed name, and link feeds to Miniflux for admins

Readers see "Feed · Publication" on the issue, article, public and RSS
pages and in the EPUB index and chapter headers; the publication is the
page's site name, else its domain, and is dropped when it would repeat
the feed's title. Admins get the feed name linked to its Miniflux page.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YWmCpUojfHXhSZ2129Z7Nv

src/web/templates/_source.html

@@ -0,0 +1 @@
+{% match source.feed_href %}{% when Some with (href) %}<a class="text-muted hover:text-accent" href="{{ href }}" target="_blank" rel="noopener">{{ source.feed_title }}</a>{% when None %}{{ source.feed_title }}{% endmatch %}{% match source.publication %}{% when Some with (publication) %} · {{ publication }}{% when None %}{% endmatch %}