Fix: Karte nicht sichtbar - Container-Hoehe in gridstack korrigiert

- map-card: position absolute + inset 0 (zuverlaessig in gridstack)
- map-container: min-height 0 statt 200px (flex-Item braucht das)
- map-empty: position absolute statt flex-basiert
- invalidateSize mit mehreren Retries (100/300/800ms)
- Bounds werden nach invalidateSize erneut gesetzt

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/static/css/style.css

@@ -4145,9 +4145,11 @@ a:hover {
 
 /* === Karten-Kachel (Leaflet) === */
 .map-card {
+    position: absolute;
+    inset: 0;
     display: flex;
     flex-direction: column;
-    height: 100%;
+    overflow: hidden;
 }
 .map-card .card-header {
     flex-shrink: 0;
@@ -4159,16 +4161,16 @@ a:hover {
 }
 .map-container {
     flex: 1;
-    min-height: 200px;
     position: relative;
     z-index: 1;
+    min-height: 0;
 }
 .map-empty {
     display: flex;
     align-items: center;
     justify-content: center;
-    height: 100%;
-    min-height: 200px;
+    position: absolute;
+    inset: 0;
     color: var(--text-tertiary);
     font-size: 13px;
     font-family: var(--font-body);