feat(sync): synchronize Hiboutik data through POST /sync

POST /sync starts the full synchronization in the background (202, or 409 when one is already running). Entities are synced in dependency order: brands, categories, suppliers, products (with versions and stocks), customers. Each row is synced independently so that a failure is logged without stopping the rest. Replaces the default AppService.

src/utils/sync.ts

@@ -0,0 +1,24 @@
+import { Logger } from '@nestjs/common';
+
+/**
+ * Runs `action` on each item, one at a time: a failing item is logged and skipped, the others are still processed.
+ * @param describe label of an item in the error log, e.g. "Hiboutik brand 12".
+ * @returns the number of failed items.
+ */
+export async function forEachSafely<T>(
+  items: T[],
+  action: (item: T) => Promise<unknown>,
+  logger: Logger,
+  describe: (item: T) => string,
+): Promise<number> {
+  let nbFailed = 0;
+  for (const item of items) {
+    try {
+      await action(item);
+    } catch (error) {
+      nbFailed++;
+      logger.error(`Failed to sync ${describe(item)}`, (error as Error)?.stack);
+    }
+  }
+  return nbFailed;
+}