fix(downloads): harden queue controls and resumable replacement

Prevent queue action clicks from triggering row double-clicks, preserve aria2/yt-dlp resumable sidecars during duplicate replacement, and make aria2 require resume instead of silently restarting.

Add a persisted, accessible Folders collapse control with reduced-motion animation and regression coverage for replacement sidecar handling.

Fixes #11

Fixes #12

Closes #13

Refs #14

src-tauri/src/lib.rs

@@ -3475,8 +3475,10 @@ async fn remove_download(
     state: tauri::State<'_, AppState>,
     id: String,
     delete_assets: bool,
+    preserve_resumable: Option<bool>,
 ) -> Result<(), String> {
     log::info!("remove_download called for id: {}", id);
+    let preserve_resumable = preserve_resumable.unwrap_or(false);
     let primary_path = crate::download_ownership::primary_path_for_id(&app_handle, &id)?;
 
     let active_kind = state.queue_manager.active_kind(&id).await;
@@ -3535,8 +3537,13 @@ async fn remove_download(
         crate::ipc::DownloadStateEvent::new(id.clone(), crate::ipc::DownloadStatus::Paused),
     );
 
+    let preserve_assets = preserve_resumable
+        && primary_path
+            .as_deref()
+            .is_some_and(has_resumable_download_assets);
+
     let cleanup_result = async {
-        if delete_assets {
+        if delete_assets && !preserve_assets {
             if let Some(path) = primary_path.as_deref() {
                 remove_download_assets(path, &app_handle).await?;
             }
@@ -3550,6 +3557,14 @@ async fn remove_download(
     cleanup_result
 }
 
+fn has_resumable_download_assets(primary: &std::path::Path) -> bool {
+    [".aria2", ".part", ".ytdl"].iter().any(|suffix| {
+        let mut candidate = primary.as_os_str().to_os_string();
+        candidate.push(suffix);
+        std::path::PathBuf::from(candidate).exists()
+    })
+}
+
 pub(crate) async fn remove_download_assets<R: tauri::Runtime>(
     primary: &std::path::Path,
     app_handle: &tauri::AppHandle<R>,
@@ -4802,7 +4817,8 @@ mod tests {
         normalize_speed_limit_for_aria2,
         parse_firelink_deep_link, parse_ffmpeg_version, parse_media_progress_line,
         redact_log_line, redact_log_line_for_output, sanitize_ytdlp_config_value,
-        should_cleanup_media_artifacts_after_failure, FirelinkDeepLink, MediaProgress,
+        has_resumable_download_assets, should_cleanup_media_artifacts_after_failure,
+        FirelinkDeepLink, MediaProgress,
         MediaSpeedSampler, MEDIA_PROGRESS_PREFIX,
     };
     use serde_json::json;
@@ -4825,6 +4841,18 @@ mod tests {
         assert_eq!(template, destination.join("clip.mp4"));
     }
 
+    #[test]
+    fn recognizes_resume_sidecars_without_treating_the_primary_file_as_partial() {
+        let directory = tempfile::tempdir().unwrap();
+        let primary = directory.path().join("download.bin");
+        std::fs::write(&primary, b"partial").unwrap();
+
+        assert!(!has_resumable_download_assets(&primary));
+
+        std::fs::write(directory.path().join("download.bin.aria2"), b"control").unwrap();
+        assert!(has_resumable_download_assets(&primary));
+    }
+
     #[test]
     fn ytdlp_progress_args_force_progress_in_quiet_print_mode() {
         let args = media_progress_args();

src-tauri/src/queue.rs

@@ -1248,6 +1248,8 @@ impl SidecarSpawner for ProductionSpawner {
         options.insert("max-tries".to_string(), serde_json::json!(mt.to_string()));
         options.insert("retry-wait".to_string(), serde_json::json!("2"));
         options.insert("continue".to_string(), serde_json::json!("true"));
+        options.insert("always-resume".to_string(), serde_json::json!("true"));
+        options.insert("auto-file-renaming".to_string(), serde_json::json!("false"));
         if let Some(speed) = payload
             .speed_limit
             .as_deref()