fix(frontend): app.js Cache-Buster bumpen damit I18N.load() greift

Bei Phase 6 wurde components.js und i18n.js gebumpt, app.js aber nicht.
Browser zogen die alte app.js ohne I18N-Init aus dem Cache, sodass
eng_demo-Nutzer eine deutsche Oberflaeche sahen.

src/static/dashboard.html

@@ -729,7 +729,7 @@
     <script src="/static/js/components.js?v=20260513a"></script>
     <script src="/static/js/layout.js?v=20260316b"></script>
     <script src="/static/js/pipeline.js?v=20260501i"></script>
-    <script src="/static/js/app.js?v=20260512a"></script>
+    <script src="/static/js/app.js?v=20260513b"></script>
     <script src="/static/js/cluster-data.js?v=20260322f"></script>
     <script src="/static/js/tutorial.js?v=20260316z"></script>
     <script src="/static/js/chat.js?v=20260422a"></script>