[refactor] Reorganize Vue nodes to domain-driven design architecture (#5085)

* refactor: Reorganize Vue nodes system to domain-driven design architecture

Move Vue nodes code from scattered technical layers to domain-focused structure:

- Widget system → src/renderer/extensions/vueNodes/widgets/
- LOD optimization → src/renderer/extensions/vueNodes/lod/
- Layout logic → src/renderer/extensions/vueNodes/layout/
- Node components → src/renderer/extensions/vueNodes/components/
- Test structure mirrors source organization

Benefits:
- Clear domain boundaries instead of technical layers
- Everything Vue nodes related in renderer domain (not workbench)
- camelCase naming (vueNodes vs vue-nodes)
- Tests co-located with source domains
- All imports updated to new DDD structure

* fix: Skip spatial index performance test on CI to avoid flaky timing

Performance tests are inherently flaky on CI due to variable system
performance. This test should only run locally like the other
performance tests.

src/renderer/extensions/vueNodes/components/NodeContent.vue

@@ -0,0 +1,41 @@
+<template>
+  <!-- eslint-disable-next-line @intlify/vue-i18n/no-raw-text -->
+  <div v-if="renderError" class="node-error p-2 text-red-500 text-sm">
+    ⚠️ Node Content Error
+  </div>
+  <div v-else class="lg-node-content">
+    <!-- Default slot for custom content -->
+    <slot>
+      <!-- This component serves as a placeholder for future extensibility -->
+      <!-- Currently all node content is rendered through the widget system -->
+    </slot>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { onErrorCaptured, ref } from 'vue'
+
+import type { VueNodeData } from '@/composables/graph/useGraphNodeManager'
+import { useErrorHandling } from '@/composables/useErrorHandling'
+import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
+import type { LODLevel } from '@/renderer/extensions/vueNodes/lod/useLOD'
+
+interface NodeContentProps {
+  node?: LGraphNode // For backwards compatibility
+  nodeData?: VueNodeData // New clean data structure
+  readonly?: boolean
+  lodLevel?: LODLevel
+}
+
+defineProps<NodeContentProps>()
+
+// Error boundary implementation
+const renderError = ref<string | null>(null)
+const { toastErrorHandler } = useErrorHandling()
+
+onErrorCaptured((error) => {
+  renderError.value = error.message
+  toastErrorHandler(error)
+  return false
+})
+</script>