knowledgebase: include the topic (application name) in list search

The KB list search matched only shortdescription + keywords, so searching a
topic (e.g. "Spotfire", the Application name) surfaced just the one article
whose title/keywords contained the word, not the others tied to it by topic.
Match the topic too via an appid IN (apps named like the term) subquery - used
instead of a join so it does not collide with the sort=topic join, and articles
with no app still match on title/keywords.

plugins/knowledgebase/api/routes.py

@@ -29,12 +29,19 @@ def list_articles():
 
     query = KnowledgeBase.query.filter_by(isactive=True)
 
-    # Search
+    # Search: title, keywords, and the topic (its Application's name). The topic
+    # is matched via an appid subquery instead of a join so it does not collide
+    # with the sort=='topic' join below; articles with no app just miss that
+    # clause and still match on title/keywords.
     if search := request.args.get('search'):
+        like = f'%{search}%'
+        topic_appids = db.session.query(Application.appid).filter(
+            Application.appname.ilike(like))
         query = query.filter(
             db.or_(
-                KnowledgeBase.shortdescription.ilike(f'%{search}%'),
-                KnowledgeBase.keywords.ilike(f'%{search}%')
+                KnowledgeBase.shortdescription.ilike(like),
+                KnowledgeBase.keywords.ilike(like),
+                KnowledgeBase.appid.in_(topic_appids)
             )
         )