Play and delete a torrent that came as a folder of files (#158)

A torrent of several files is recorded as its folder. /media could not serve a folder, and the
reaper's remove_file failed on it, warned "could not delete" on every pass and freed nothing, so it
counted against the quota for good; Delete in the page failed the same way.

download::remove deletes a file or a whole folder, for the reaper and Delete alike, and the reaper
counts a folder by its recorded size, as a directory's own size is not its contents'.
download::playable answers the path itself, or for a folder the largest file in it, which is the
episode, and /media serves that.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/web.rs

@@ -1758,7 +1758,7 @@ async fn delete_file(
         }
     }
     if let Some(path) = &enc.path
-        && let Err(e) = std::fs::remove_file(path)
+        && let Err(e) = crate::download::remove(std::path::Path::new(path))
         && e.kind() != std::io::ErrorKind::NotFound
     {
         return Err(e.into());
@@ -1863,7 +1863,7 @@ async fn media(
     let Some(path) = enc.path else {
         return (StatusCode::NOT_FOUND, "not downloaded").into_response();
     };
-    match ServeFile::new(path).oneshot(req).await {
+    match ServeFile::new(crate::download::playable(std::path::Path::new(&path))).oneshot(req).await {
         Ok(r) => r.into_response(),
         Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
     }