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/shared/apiRelations.ts

@@ -0,0 +1,56 @@
+export const RELATION_ID_MAP: Record<string, { key: string; path: string }> = {
+  siteId: { key: 'site', path: 'sites' },
+  machineId: { key: 'machine', path: 'machines' },
+  composantId: { key: 'composant', path: 'composants' },
+  pieceId: { key: 'piece', path: 'pieces' },
+  productId: { key: 'product', path: 'products' },
+  typeComposantId: { key: 'typeComposant', path: 'model_types' },
+  typePieceId: { key: 'typePiece', path: 'model_types' },
+  typeProductId: { key: 'typeProduct', path: 'model_types' },
+};
+
+export const toIri = (path: string, id: string): string => `/api/${path}/${id}`;
+
+export const extractRelationId = (value: unknown): string | null => {
+  if (!value) {
+    return null;
+  }
+  if (typeof value === 'string') {
+    const trimmed = value.trim();
+    if (!trimmed) {
+      return null;
+    }
+    if (trimmed.includes('/')) {
+      const parts = trimmed.split('/').filter(Boolean);
+      return parts.length ? (parts[parts.length - 1] ?? null) : null;
+    }
+    return trimmed;
+  }
+  if (typeof value === 'object' && 'id' in (value as Record<string, any>)) {
+    const id = (value as Record<string, any>).id;
+    return typeof id === 'string' ? id : null;
+  }
+  return null;
+};
+
+export const normalizeRelationIds = <T extends Record<string, any>>(payload: T): T => {
+  if (!payload || typeof payload !== 'object') {
+    return payload;
+  }
+
+  const next: Record<string, any> = { ...payload };
+  Object.entries(RELATION_ID_MAP).forEach(([sourceKey, config]) => {
+    const raw = next[sourceKey];
+    if (typeof raw !== 'string') {
+      return;
+    }
+    const trimmed = raw.trim();
+    if (!trimmed) {
+      return;
+    }
+    next[config.key] = toIri(config.path, trimmed);
+    delete next[sourceKey];
+  });
+
+  return next as T;
+};