test(arr): read available_engines from the build

Second test that assumed the empty default feature set. It asserted
available_engines was literally [], which --all-features makes false.

crates/arr-api/src/subtitle_settings.rs

@@ -255,7 +255,7 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn the_seeded_row_reads_back_with_no_engines_compiled() {
+    async fn the_seeded_row_reads_back_with_the_engines_this_build_compiled() {
         let (_dir, base) = application().await;
         let settings: serde_json::Value = reqwest::get(format!("{base}/api/settings/subtitles"))
             .await
@@ -272,7 +272,12 @@ mod tests {
             serde_json::json!(["opensubtitles", "podnapisi"])
         );
         assert!(settings["translation_engine"].is_null());
-        assert_eq!(settings["available_engines"], serde_json::json!([]));
+        // `available_engines` is a fact about the build, not about the seed
+        // row, so it tracks the `translate-*` features rather than a literal.
+        assert_eq!(
+            settings["available_engines"],
+            serde_json::json!(arr_subs::compiled_engines())
+        );
     }
 
     #[tokio::test]