perf(falukant): deploy prebuilt models and release WebGL contexts

frontend/src/components/Character3D.vue

@@ -332,7 +332,7 @@ export default {
       // Renderer erstellen
       this.renderer = markRaw(new runtime.WebGLRenderer({ antialias: true, alpha: true }));
       this.renderer.setSize(container.clientWidth, container.clientHeight);
-      this.renderer.setPixelRatio(window.devicePixelRatio);
+      this.renderer.setPixelRatio(Math.min(window.devicePixelRatio || 1, 2));
       container.appendChild(this.renderer.domElement);
 
       // Verbesserte Beleuchtung für kräftigere Farben
@@ -687,7 +687,12 @@ export default {
         if (container && this.renderer.domElement) {
           container.removeChild(this.renderer.domElement);
         }
+        // dispose() alone leaves the browser context alive until garbage
+        // collection. Route changes or long character lists can otherwise
+        // exceed Chromium's context limit and crash the tab.
+        this.renderer.forceContextLoss?.();
         this.renderer.dispose();
+        this.renderer = null;
       }
 
       if (this.scene) {

frontend/src/components/falukant/House3D.vue

@@ -124,9 +124,15 @@ export default {
       this.removeModel();
       if (this.renderer) {
         this.$refs.container?.removeChild(this.renderer.domElement);
+        // Release immediately instead of waiting for garbage collection.
+        // Several house previews otherwise accumulate WebGL contexts.
+        this.renderer.forceContextLoss?.();
         this.renderer.dispose();
+        this.renderer = null;
       }
       this.scene?.clear();
+      this.scene = null;
+      this.camera = null;
     },
   },
 };