fix(falukant): revalidate replaced character meshes

backend/routers/modelsProxyRouter.js

@@ -14,7 +14,10 @@ router.get('/3d/falukant/characters/:filename', async (req, res) => {
   try {
     const cachePath = await getOptimizedModelPath(filename);
     res.setHeader('Content-Type', 'model/gltf-binary');
-    res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
+    // GLB files can be replaced under the same filename during an asset deploy.
+    // Revalidate cached copies so clients receive a changed mesh without needing
+    // to clear their browser cache.
+    res.setHeader('Cache-Control', 'public, max-age=0, must-revalidate');
     res.sendFile(cachePath);
   } catch (e) {
     if (e.message?.includes('Invalid model filename') || e.message?.includes('not found')) {

frontend/src/components/Character3D.vue

@@ -27,6 +27,10 @@ import { getApiBaseURL } from '@/utils/axios.js';
 /** Backend-Route: GET /api/models/3d/falukant/characters/:filename (Proxy mit Draco-Optimierung) */
 const MODELS_API_PATH = '/api/models/3d/falukant/characters';
 const OPTIMIZED_MODEL_SUFFIX = '_opt.glb';
+// Bump this when deployment replaces GLB files under unchanged filenames.
+// The revision is part of the URL, so a browser cannot reuse an older immutable
+// response for the same model file.
+const MODEL_ASSET_REVISION = '20260930-2';
 // Only concrete age models are used. If an exact age is not available, choose
 // the nearest lower one instead of the generic gender/age-group fallback.
 const AVAILABLE_MODEL_AGES = Object.freeze({
@@ -456,7 +460,7 @@ export default {
           .filter((age) => age <= modelAge)
           .sort((left, right) => right - left);
         const candidates = candidateAges.map((age) =>
-          `${prefix}/${this.actualGender}_${age}y${OPTIMIZED_MODEL_SUFFIX}`
+          `${prefix}/${this.actualGender}_${age}y${OPTIMIZED_MODEL_SUFFIX}?v=${MODEL_ASSET_REVISION}`
         );
 
         let gltf;