fix: copy scratch-storage webpack chunks to prevent loading hangs

Apply fix from upstream scratch-gui PR scratchfoundation#9885 to resolve asset loading
timeouts by ensuring scratch-storage's dynamically imported chunks
are copied to the build output.

Original patch: scratchfoundation#9885
Copyright belongs to the original patch author.

Fixes asset loading hangs where super.load() would timeout after 10 seconds
for certain asset IDs (e.g., bcf454acf82e4504149f7ffe07081dbc).

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: takaokouji

webpack.config.js

@@ -80,6 +80,11 @@ const baseConfig = new ScratchWebpackConfigBuilder(
                 context: 'node_modules/scratch-vm/dist/web',
                 from: 'extension-worker.{js,js.map}',
                 noErrorOnMissing: true
+            },
+            {
+                context: 'node_modules/scratch-storage/dist/web',
+                from: 'chunks/*.{js,js.map}',
+                noErrorOnMissing: true
             }
         ]
     }));