Initial commit: 3D Viewer application

Features:
- Vue 3 frontend with Three.js/Online3DViewer
- Node.js API with PostgreSQL and Redis
- Python worker for model conversion
- Docker Compose for deployment
- ViewCube navigation with drag rotation and 90° snap
- Cross-section, exploded view, and render settings
- Parts tree with visibility controls

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/viewer/FeaturePanel.vue

@@ -0,0 +1,18 @@
+<script setup lang="ts">
+import { useViewerStore } from '@/stores/viewer'
+import ExplodedView from './ExplodedView.vue'
+import CrossSection from './CrossSection.vue'
+import RenderSettings from './RenderSettings.vue'
+import ThumbnailCapture from './ThumbnailCapture.vue'
+
+const viewerStore = useViewerStore()
+</script>
+
+<template>
+  <div v-if="viewerStore.model" class="feature-panel">
+    <RenderSettings />
+    <ExplodedView />
+    <CrossSection />
+    <ThumbnailCapture />
+  </div>
+</template>