Rename PlayRequest/PlayResponse to QueueRequest/QueueResponse

Updated DTOs and endpoint logic to reflect the separation of search result resolution and playback queuing. Adjusted references to `/play` and `/play/select` routes, replacing them with clearer `/search` and `/queue` endpoints in comments, documentation, and API definitions.

src/main/java/me/bobert/netneutrality/music/SearchResultHandler.java

@@ -24,7 +24,7 @@ import java.util.concurrent.CompletableFuture;
 /**
  * Translates a Lavalink load result into a {@link PlayOutcome} without ever queuing anything, so
  * that every REST load request, not only ambiguous text searches, requires a separate
- * {@code /play} call with {@code searchId}/{@code index} to actually queue a track.
+ * {@code /music/{guildId}/queue} call with {@code searchId}/{@code index} to actually queue a track.
  *
  * <p>A single resolved track, the tracks of a playlist, and ambiguous search results are each
  * stashed as candidates in {@link PendingSearchResults} and reported back with their own