fix file created_at not working on some targets

backend/Cargo.toml

@@ -22,6 +22,7 @@ dotenv = "0.15.0"
 hex = "0.4.3"
 mime_guess = "2.0.5"
 regex = "1.11.1"
+rustix = { version = "1.0.8", features = ["fs"] }
 serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
 sqlx = { version = "0.8.6", features = ["chrono", "postgres", "runtime-tokio", "time", "uuid"] }