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/pages/component-category/index.vue

@@ -0,0 +1,10 @@
+<template>
+  <ManagementView
+    category="COMPONENT"
+    heading="Catégories de composant"
+  />
+</template>
+
+<script setup lang="ts">
+import ManagementView from '~/components/model-types/ManagementView.vue'
+</script>