Changed config to a singleton pattern, updated state and config trait by adding resolver variant.

Updated README to reflect current structure approach.

README.md

@@ -19,11 +19,14 @@ assets/
    generic/
       intro/
          Intro_MrNewVegas_N.mp3
+      shared/
+         Story_MrNewVegas_N.mp3
       news/
          story_N/
-            story.toml (ignored, metadata)
+            story.toml (optional, ignored)
             Story_MrNewVegas_N.mp3
             Story_Guest_N.mp3
+            Story_MrNewVegas_N.mp3 -> symlink shared/Story_MrNewVegas_N.mp3
    .cache/ (automatically generated)
       songs/
          my_song/
@@ -32,11 +35,16 @@ assets/
             cache.json
       generic/
          intro/
-            Intro_MrNewVegas_N.pcm (f32 pcm)
-            Intro_MrNewVegas_N.cache.json
+            intro_N.pcm (f32 pcm)
+            intro_N.cache.json
+         shared/
+            story_N.pcm (f32 pcm)
+            story_N.cache.json
          news/
             story_N/
                part_N.pcm (f32 pcm)
+               part_N.pcm (f32 pcm)
+               part_N.pcm (f32 pcm) -> symlink shared/story_N.pcm
                cache.json
 ```