fix(backend): match the authenticated user into get/download/delete operations

backend/.sqlx/query-24fd2306e40be21dc82660ec3f42f95928849706ecb75fe1cb8b606aa3cf2971.json

@@ -0,0 +1,40 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n            SELECT *\n            FROM users u\n            WHERE u.username = $1\n            ",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "id",
+        "type_info": "Int8"
+      },
+      {
+        "ordinal": 1,
+        "name": "username",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 2,
+        "name": "password_hash",
+        "type_info": "Text"
+      },
+      {
+        "ordinal": 3,
+        "name": "created_at",
+        "type_info": "Timestamptz"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Text"
+      ]
+    },
+    "nullable": [
+      false,
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "24fd2306e40be21dc82660ec3f42f95928849706ecb75fe1cb8b606aa3cf2971"
+}