Reorganize app workspaces and align Admin architecture

apps/backend/app/validators/schemas/create_file_input_schema.ts

@@ -0,0 +1,23 @@
+import { VineMultipartFile } from '@adonisjs/core/vine'
+import { OptionalModifier } from '@vinejs/vine/schema/base/literal'
+import vine from '@vinejs/vine'
+
+/**
+ * Creates a reusable upload file schema that requires either:
+ * - `ref` (reference to an existing file), or
+ * - `file` (new uploaded file).
+ *
+ * At least one field must be present. When `ref` is missing, `file`
+ * becomes required. When `file` is missing, `ref` becomes required.
+ *
+ * @param fileScheme Custom optional file validation schema.
+ * @returns Vine object schema with mutually dependent `ref` and `file` fields.
+ */
+export default function createFileInputSchema(
+  fileScheme: OptionalModifier<VineMultipartFile> = vine.file({ size: '5mb' }).optional()
+) {
+  return vine.object({
+    ref: vine.string().optional().requiredIfMissing('file'),
+    file: fileScheme.requiredIfMissing('ref'),
+  })
+}