chore: relocate backend into apps/api ahead of monorepo merge

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/api/middleware/task_upload.middleware.js

@@ -0,0 +1,50 @@
+/***********************************************************************************************************************************************************************
+ * File Name: taskUpload.middleware.js
+ * Type of Program: Middleware
+ * Description: Multer config for task completion file uploads.
+ *              Uses memory storage — buffer is passed directly to S3.
+ *              Single file per request (matches the two-step upload flow in
+ *              ViewTaskDetails where each file is uploaded individually).
+ *
+ * Limits:
+ *   fileSize: 500 MB (matches FileUpload.jsx DEFAULT_MAX_BYTES)
+ *
+ * Author: rgrgogu
+ * Date Created: Jun. 13, 2026
+ ***********************************************************************************************************************************************************************/
+const multer = require('multer');
+
+const storage = multer.memoryStorage();
+
+const upload = multer({
+    storage,
+    limits: {
+        fileSize: 500 * 1024 * 1024, // 500 MB
+    },
+});
+
+// Single file per request — field name must be "file"
+const uploadTaskFile = upload.single('file');
+
+// ─── Error wrapper ────────────────────────────────────────────────────────────
+// Converts multer errors to a consistent R.error-style response.
+const handleUpload = (req, res, next) => {
+    uploadTaskFile(req, res, (err) => {
+        if (!err) return next();
+
+        if (err.code === 'LIMIT_FILE_SIZE') {
+            return res.status(400).json({
+                status: 'error',
+                message: 'File exceeds the 500 MB size limit.',
+            });
+        }
+
+        console.error('[MULTER ERROR]', err);
+        return res.status(400).json({
+            status: 'error',
+            message: err.message ?? 'File upload failed.',
+        });
+    });
+};
+
+module.exports = { handleUpload };