perf(falukant): simplify house runtime geometry

frontend/scripts/build-falukant-runtime-models.mjs

@@ -16,13 +16,20 @@ const scriptDir = path.dirname(fileURLToPath(import.meta.url));
 const frontendDir = path.resolve(scriptDir, '..');
 const args = process.argv.slice(2);
 const optionIndex = args.indexOf('--assets-dir');
+const categoryIndex = args.indexOf('--category');
 const assetsDir = path.resolve(optionIndex >= 0 && args[optionIndex + 1]
   ? args[optionIndex + 1]
   : path.join(frontendDir, '..', '..', 'YourPart3Assets'));
 const sourceRoot = path.join(assetsDir, 'models-src', '3d', 'falukant');
 const outputRoot = path.join(assetsDir, 'public', 'models', '3d', 'falukant');
 
-for (const category of ['characters', 'houses']) {
+const selectedCategory = categoryIndex >= 0 ? args[categoryIndex + 1] : null;
+const categories = selectedCategory ? [selectedCategory] : ['characters', 'houses'];
+if (categories.some((category) => !['characters', 'houses'].includes(category))) {
+  throw new Error('Use --category characters or --category houses.');
+}
+
+for (const category of categories) {
   const sourceDir = path.join(sourceRoot, category);
   const outputDir = path.join(outputRoot, category);
   if (!fs.existsSync(sourceDir)) {

frontend/scripts/optimize-glb.mjs

@@ -62,6 +62,7 @@ function optimizeModelDirectory({ name, sourceDir, outputDir, required = false }
   }
 
   console.log(`Optimize Falukant ${name} GLBs (Draco + texture 1024)\n`);
+  const isHouse = name === 'house' || name === 'houses' || path.basename(sourceDir) === 'houses';
 
   for (const f of models) {
     const input = path.join(sourceDir, f);
@@ -71,7 +72,16 @@ function optimizeModelDirectory({ name, sourceDir, outputDir, required = false }
     try {
       const result = spawnSync(
         'node',
-        [cli, 'optimize', input, output, '--compress', 'draco', '--texture-size', '1024'],
+        [
+          cli, 'optimize', input, output,
+          '--compress', 'draco',
+          '--texture-size', '1024',
+          // Draco reduces download size, while simplify prevents high-poly
+          // scans from exhausting browser GPU memory. Houses are small
+          // previews, so they get a deliberately stronger reduction.
+          '--simplify-ratio', isHouse ? '0.05' : '0.35',
+          '--simplify-error', isHouse ? '0.02' : '0.01',
+        ],
         {
           stdio: 'inherit',
           cwd: path.join(__dirname, '..'),