Remove Lavaplayer and migrate to Lavalink

Replaced the bot's audio handling system by removing Lavaplayer dependencies and migrating to a Lavalink v4 node. Updated `MusicManager`, `TrackScheduler`, and related classes to utilize the `LavalinkClient`. Refactored playlist and track loading logic, task integrations, and event dispatch to integrate with the remote node. Deprecated the custom Udio source, preserving references for a future plugin port. Documented configuration and deployment details for the new audio architecture.

docs/reference/udio-lavalink-plugin/UdioAudioTrack.java

@@ -0,0 +1,80 @@
+package me.bobert.netneutrality.music.source;
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import com.sedmelluq.discord.lavaplayer.container.mp3.Mp3AudioTrack;
+import com.sedmelluq.discord.lavaplayer.tools.FriendlyException;
+import com.sedmelluq.discord.lavaplayer.tools.JsonBrowser;
+import com.sedmelluq.discord.lavaplayer.tools.io.HttpClientTools;
+import com.sedmelluq.discord.lavaplayer.tools.io.HttpInterface;
+import com.sedmelluq.discord.lavaplayer.tools.io.PersistentHttpStream;
+import com.sedmelluq.discord.lavaplayer.track.AudioTrackInfo;
+import com.sedmelluq.discord.lavaplayer.track.DelegatedAudioTrack;
+import com.sedmelluq.discord.lavaplayer.track.playback.LocalAudioTrackExecutor;
+import org.apache.commons.io.IOUtils;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.io.IOException;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+
+import static com.sedmelluq.discord.lavaplayer.tools.FriendlyException.Severity.SUSPICIOUS;
+
+public class UdioAudioTrack extends DelegatedAudioTrack {
+
+    private static final Logger log = LogManager.getLogger(UdioAudioTrack.class);
+
+    private final UdioAudioSourceManager sourceManager;
+
+    /**
+     * @param trackInfo     Track info
+     * @param sourceManager Source manager which was used to find this track
+     */
+    public UdioAudioTrack(AudioTrackInfo trackInfo, UdioAudioSourceManager sourceManager) {
+        super(trackInfo);
+
+        this.sourceManager = sourceManager;
+    }
+
+    @Override
+    public void process(LocalAudioTrackExecutor localExecutor) throws Exception {
+        try (HttpInterface httpInterface = sourceManager.getHttpInterface()) {
+            String playbackUrl = loadPlaybackUrl(httpInterface);
+
+            log.debug("Starting Udio track from URL: {}", playbackUrl);
+
+            try (PersistentHttpStream stream = new PersistentHttpStream(httpInterface, new URI(playbackUrl), null)) {
+                processDelegate(new Mp3AudioTrack(trackInfo, stream), localExecutor);
+            }
+        }
+    }
+
+    private String loadPlaybackUrl(HttpInterface httpInterface) throws IOException {
+        JsonBrowser trackInfo = loadTrackInfo(httpInterface);
+
+        if (trackInfo == null) {
+            throw new FriendlyException("Udio: Failed to extract track information from web page.", SUSPICIOUS, null);
+        }
+
+        return trackInfo.get("song_path").text();
+    }
+
+    private JsonBrowser loadTrackInfo(HttpInterface httpInterface) throws IOException {
+        try (CloseableHttpResponse response = httpInterface.execute(new HttpGet(trackInfo.identifier))) {
+            int statusCode = response.getStatusLine().getStatusCode();
+
+            if (!HttpClientTools.isSuccessWithContent(statusCode)) {
+                throw new FriendlyException("Server responded with an error.", SUSPICIOUS,
+                    new IllegalStateException("Response code for player config is " + statusCode));
+            }
+
+            return sourceManager.loadTrackInfoFromPageContent(IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8));
+        }
+    }
+}