fix: Include extensions and renderer in knip entry points

Knip was incorrectly flagging 'three' and 'yjs' as unused dependencies
because the configuration didn't include their usage in extensions and
renderer modules as entry points.

- Add src/extensions/**/*.ts to detect 'three' usage in load3d extension
- Add src/renderer/**/*.ts to detect 'yjs' usage in layout components

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

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

knip.config.ts

@@ -8,7 +8,11 @@ const config: KnipConfig = {
         'src/assets/css/style.css',
         'src/main.ts',
         'src/scripts/ui/menu/index.ts',
-        'src/types/index.ts'
+        'src/types/index.ts',
+        // Include extension entry points to detect dependencies like 'three'
+        'src/extensions/**/*.ts',
+        // Include core renderer components to detect dependencies like 'yjs'
+        'src/renderer/**/*.ts'
       ],
       project: ['**/*.{js,ts,vue}', '*.{js,ts,mts}']
     },