feat(sources): Quellenuebersicht der Lage nach Typ filterbar

Die Quellenuebersicht innerhalb einer Lage zeigt jetzt Filter-Chips
(Alle / Web / Telegram / X) und blendet die Quellen-Boxen nach
Quellentyp ein und aus. Die Chips erscheinen nur, wenn neben Web auch
Telegram- oder X-Quellen vorkommen.

- sources-summary-Endpoint liefert pro Quelle einen source_type,
  abgeleitet aus dem source-Praefix (X: / Telegram: / sonst Web)
- Filter-Chips und data-type in renderSourceOverviewFromSummary
- App.filterSourceOverview blendet die Boxen nach Typ
- Chip-Styles in style.css

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/static/dashboard.html

@@ -13,7 +13,7 @@
     <link rel="stylesheet" href="/static/vendor/leaflet.css">
     <link rel="stylesheet" href="/static/vendor/MarkerCluster.css">
     <link rel="stylesheet" href="/static/vendor/MarkerCluster.Default.css">
-    <link rel="stylesheet" href="/static/css/style.css?v=20260501h">
+    <link rel="stylesheet" href="/static/css/style.css?v=20260522c">
 <style>
 /* Export Modal Radio */
 .export-radio { display:flex; align-items:center; gap:10px; padding:8px 12px; cursor:pointer; border-radius:var(--radius-sm); transition:background 0.15s; border:1px solid transparent; margin-bottom:4px; }
@@ -807,10 +807,10 @@
     <script src="/static/js/i18n.js?v=20260513a"></script>
     <script src="/static/js/api.js?v=20260423a"></script>
     <script src="/static/js/ws.js?v=20260316b"></script>
-    <script src="/static/js/components.js?v=20260522b"></script>
+    <script src="/static/js/components.js?v=20260522c"></script>
     <script src="/static/js/layout.js?v=20260513f"></script>
     <script src="/static/js/pipeline.js?v=20260513d"></script>
-    <script src="/static/js/app.js?v=20260522a"></script>
+    <script src="/static/js/app.js?v=20260522c"></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=20260514e"></script>