Applications: show related knowledge-base articles on the app detail

Classic ShopDB listed an application's related KB articles on its page; the flask
app detail didn't, even though KB articles carry an appid FK. get_application now
returns a knowledgebase list (KB rows linked by appid; lazy + plugin-guarded so
core stays decoupled), and ApplicationDetail.vue renders a Knowledge Base section
linking each article.

Verified: an app returns its linked KB (e.g. 77 articles) and the section renders.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/applications/ApplicationDetail.vue

@@ -93,6 +93,23 @@
               </div>
             </div>
           </div>
+
+          <!-- Related Knowledge Base -->
+          <div class="section-card" v-if="app.knowledgebase && app.knowledgebase.length">
+            <h3 class="section-title">Knowledge Base ({{ app.knowledgebase.length }})</h3>
+            <div class="kb-list">
+              <a
+                v-for="kb in app.knowledgebase"
+                :key="kb.linkid"
+                :href="kb.linkurl"
+                target="_blank"
+                class="kb-item"
+              >
+                <span class="kb-title">{{ kb.shortdescription }}</span>
+                <span class="kb-keywords" v-if="kb.keywords">{{ kb.keywords }}</span>
+              </a>
+            </div>
+          </div>
         </div>
 
         <!-- Right Column -->