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/App.vue

@@ -0,0 +1,20 @@
+<script setup lang="ts">
+import { onMounted, onUnmounted } from 'vue'
+import { useModelsStore } from '@/stores/models'
+import AppLayout from '@/components/layout/AppLayout.vue'
+
+const modelsStore = useModelsStore()
+
+onMounted(async () => {
+  await modelsStore.fetchModels()
+  modelsStore.startPolling(5000)
+})
+
+onUnmounted(() => {
+  modelsStore.stopPolling()
+})
+</script>
+
+<template>
+  <AppLayout />
+</template>