feat(io): bundle background music as classpath resources

Switch OggMusicBackend from streaming an external, git-ignored music/ folder
(relative to the run directory) to streaming bundled classpath resources under
/music/, so the four manor tracks ship inside the JAR and play out of the box —
consistent with how fonts are bundled. The play loop reopens the resource each
iteration via a BufferedInputStream (the vorbisspi SPI needs mark/reset to read
the OGG header). Missing tracks still fall back to silence.

Add the four converted OGG Vorbis tracks (manor-theme/cellar-drone/musicbox/
lament) under src/main/resources/music/, un-ignore that path, and re-anchor the
gitignore so only the top-level MP3 source folder stays ignored. Update
docs/music.md for the bundled approach and conversion recipes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/.gitignore

@@ -44,5 +44,7 @@ build/
 # Local save games and settings
 saves/
 
-# External background-music files (not bundled)
-music/
+# Source audio (MP3 originals); only the converted .ogg under
+# src/main/resources/music/ is tracked and bundled. Anchored so it
+# ignores the top-level source folder but not the resources path.
+/music/

Semesterprojekt/docs/music.md

@@ -1,9 +1,10 @@
 # Background music (GUI)
 
-Background music plays only in the Swing GUI. It is **data-driven and external**:
+Background music plays only in the Swing GUI. It is **data-driven and bundled**:
 
-- Put `.ogg` (OGG Vorbis) files in a `music/` folder next to where you run the game.
-  This folder is git-ignored and never bundled in the JAR.
+- Tracks live as `.ogg` (OGG Vorbis) files in `src/main/resources/music/`, so they
+  are on the classpath and ship inside the JAR — the game plays music out of the box,
+  with no external folder to set up.
 - A room plays a track via an optional `music:` field in `rooms.yaml`, e.g.
   `music: manor-theme.ogg`. Entering a room with a different track fades the old one
   out and the new one in (sequential, not an overlapping cross-fade);
@@ -11,7 +12,21 @@ Background music plays only in the Swing GUI. It is **data-driven and external**
   seamlessly across rooms.
 - Volume is the **Music** setting (Off / Low / Medium / High) in the Settings menu,
   persisted to `saves/settings.json`. Off disables playback.
-- Missing files are ignored (silent) — the game never crashes over absent audio.
+- Missing tracks are ignored (silent) — the game never crashes over absent audio.
 - The console version is always silent.
 
-Decoding uses the `vorbisspi` + `jorbis` libraries via the `javax.sound` SPI.
+Decoding uses the `vorbisspi` + `jorbis` libraries via the `javax.sound` SPI;
+`OggMusicBackend` streams each track from the classpath (`/music/<track>`) on a
+daemon thread.
+
+## Adding or replacing a track
+
+1. Convert your source audio to OGG Vorbis. With ffmpeg:
+   `ffmpeg -i in.mp3 -c:a libvorbis -q:a 5 out.ogg`
+   or with gstreamer (no ffmpeg needed):
+   `gst-launch-1.0 filesrc location=in.mp3 ! decodebin ! audioconvert ! audioresample ! vorbisenc quality=0.5 ! oggmux ! filesink location=out.ogg`
+2. Drop the `.ogg` into `src/main/resources/music/`.
+3. Reference it from a room's `music:` field in `rooms.yaml`.
+
+The four tracks shipped today: `manor-theme.ogg` (ground floor),
+`cellar-drone.ogg` (cellar), `musicbox.ogg` (upper floor), `lament.ogg` (chapel).

Semesterprojekt/src/main/java/thb/jeanluc/adventure/io/OggMusicBackend.java

@@ -7,20 +7,20 @@ import javax.sound.sampled.AudioInputStream;
 import javax.sound.sampled.AudioSystem;
 import javax.sound.sampled.FloatControl;
 import javax.sound.sampled.SourceDataLine;
-import java.nio.file.Files;
-import java.nio.file.Path;
+import java.io.BufferedInputStream;
+import java.io.InputStream;
 
 /**
- * Streams OGG Vorbis tracks from the external {@code music/} folder through a
- * {@link SourceDataLine}, looping, with ~400 ms gain fades. Decoding uses the
- * vorbisspi/jorbis {@code javax.sound} SPI. All playback runs on a daemon
- * thread; missing/undecodable files are logged and stay silent. GUI-only —
- * verified manually.
+ * Streams OGG Vorbis tracks bundled on the classpath under {@code /music/}
+ * through a {@link SourceDataLine}, looping, with ~400 ms gain fades. Decoding
+ * uses the vorbisspi/jorbis {@code javax.sound} SPI. All playback runs on a
+ * daemon thread; missing/undecodable files are logged and stay silent. GUI-only
+ * — verified manually.
  */
 @Slf4j
 public final class OggMusicBackend implements MusicBackend {
 
-    private static final String MUSIC_DIR = "music";
+    private static final String MUSIC_DIR = "/music/";
     private static final int FADE_MS = 400;
     private static final int FADE_STEPS = 20;
     private static final int BUFFER = 4096;
@@ -35,13 +35,13 @@ public final class OggMusicBackend implements MusicBackend {
     public synchronized void fadeTo(String track, float gainDb) {
         stopCurrent();
         targetGainDb = gainDb;
-        Path file = Path.of(MUSIC_DIR, track);
-        if (!Files.isReadable(file)) {
-            log.warn("Music file not found, staying silent: {}", file);
+        String resource = MUSIC_DIR + track;
+        if (getClass().getResource(resource) == null) {
+            log.warn("Music resource not found, staying silent: {}", resource);
             return;
         }
         stopping = false;
-        playThread = new Thread(() -> playLoop(file, gainDb), "music");
+        playThread = new Thread(() -> playLoop(resource, gainDb), "music");
         playThread.setDaemon(true);
         playThread.start();
     }
@@ -80,11 +80,14 @@ public final class OggMusicBackend implements MusicBackend {
         playThread = null;
     }
 
-    private void playLoop(Path file, float gainDb) {
+    private void playLoop(String resource, float gainDb) {
         SourceDataLine l = null;
         try {
             while (!stopping) {
-                try (AudioInputStream in = AudioSystem.getAudioInputStream(file.toFile())) {
+                // Reopen the bundled resource each loop; BufferedInputStream gives
+                // the SPI the mark/reset support it needs to read the OGG header.
+                try (InputStream res = getClass().getResourceAsStream(resource);
+                     AudioInputStream in = AudioSystem.getAudioInputStream(new BufferedInputStream(res))) {
                     AudioFormat base = in.getFormat();
                     AudioFormat pcm = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
                             base.getSampleRate(), 16, base.getChannels(),
@@ -106,7 +109,7 @@ public final class OggMusicBackend implements MusicBackend {
                 }
             }
         } catch (Exception e) {
-            log.warn("Music playback failed for {}: {}", file, e.getMessage());
+            log.warn("Music playback failed for {}: {}", resource, e.getMessage());
         } finally {
             if (l != null) {
                 try {