refactor : merge Inventory_frontend submodule into frontend/ directory

Merges the full git history of Inventory_frontend into the monorepo
under frontend/. Removes the submodule in favor of a unified repo.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/app/components/ComponentHierarchy.vue

@@ -0,0 +1,47 @@
+<template>
+  <div class="space-y-4">
+    <!-- Root Components -->
+    <div v-for="component in components" :key="component.id" class="border border-gray-200 rounded-lg p-4">
+      <ComponentItem
+        :component="component"
+        :is-edit-mode="isEditMode"
+        :show-delete="showDelete"
+        :collapse-all="collapseAll"
+        :toggle-token="toggleToken"
+        @update="$emit('update', $event)"
+        @edit-piece="$emit('edit-piece', $event)"
+        @custom-field-update="$emit('custom-field-update', $event)"
+        @delete="$emit('delete')"
+      />
+    </div>
+  </div>
+</template>
+
+<script setup>
+import ComponentItem from './ComponentItem.vue'
+
+defineProps({
+  components: {
+    type: Array,
+    required: true
+  },
+  isEditMode: {
+    type: Boolean,
+    default: false
+  },
+  showDelete: {
+    type: Boolean,
+    default: false
+  },
+  collapseAll: {
+    type: Boolean,
+    default: true
+  },
+  toggleToken: {
+    type: Number,
+    default: 0
+  }
+})
+
+defineEmits(['update', 'edit-piece', 'custom-field-update', 'delete'])
+</script>