Stockwerksinfrastruktur zoombar gemacht

closes #30

app/assets/css/floor-infrastructure-list.css

@@ -30,6 +30,22 @@
     border-radius: 6px;
 }
 
+.infra-plan-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 10px;
+}
+
+.infra-plan-header h2 {
+    margin: 0;
+}
+
+.infra-plan-tools {
+    display: flex;
+    gap: 6px;
+}
+
 .infra-floor-canvas {
     position: relative;
     margin-top: 12px;
@@ -39,6 +55,19 @@
     border-radius: 8px;
     background: #fff;
     overflow: hidden;
+    touch-action: none;
+    cursor: grab;
+}
+
+.infra-floor-canvas.is-dragging {
+    cursor: grabbing;
+}
+
+.infra-floor-scene {
+    position: absolute;
+    inset: 0;
+    transform-origin: center center;
+    will-change: transform;
 }
 
 .infra-floor-svg {
@@ -47,6 +76,7 @@
     width: 100%;
     height: 100%;
     object-fit: contain;
+    object-position: center center;
     pointer-events: none;
     opacity: 0.85;
 }