fix(audio): remove duplicated logic and fix fader lifecycle in crossfade

lib/audio.lua

@@ -40,42 +40,31 @@ end
 --- @param ms number? in milliseconds
 function audio:crossfade(from, to, ms)
     print("[Audio]: Triggered crossfade")
+    
+    -- Stop previous 'from' if it's dangling to avoid leaks
+    if self.from and self.from ~= from and self.from ~= to then
+        self.from:stop()
+    end
+
     self:play(to)
     to:setVolume(0)
     self.from = from
     self.to = to
 
-    -- Using a dummy object to tween a value from 0 to 1
+    -- Reuse fader object to allow task cancellation
-    local fade = { value = 0 }
+    if not self.fader then self.fader = { value = 0 } end
+    self.fader.value = 0
     
-    task.tween(fade, { value = 1 }, ms or 1000, ease.easeOutCubic)(function()
-        self.from:setVolume(0)
-        self.to:setVolume(self.musicVolume)
-        self.from:stop()
-        print("[Audio]: Crossfade done")
-    end)
-    
-    -- We need a custom update loop for the volume during the tween
-    -- Since task.tween updates properties, we can use a "monitor" task or just rely on `update` if we expose the task?
-    -- Actually, task.tween updates `fade.value` every frame.
-    -- We need to apply this value to the audio sources every frame.
-    -- BUT task.tween doesn't provide an "onUpdate" callback easily. 
-    -- Workaround: create a task that runs every frame? Or modify task.tween?
-    
-    -- Let's check task.lua... it updates properties on the target object.
-    -- So `fade.value` will change. We need to apply it.
-    -- We can hook into `update` or use a metatable on `fade`?
-    
-    -- Let's use a "reactive" table with metatable setters? Overkill.
-    -- Simplest way: Add `onUpdate` to task.tween or just use `audio:update` to poll `fade.value`?
-    -- But `fade` is local.
-    
-    -- Better approach: Tween `self` properties? No, volume is on Source userdate.
-    -- Let's add a `fader` object to `self` that we tween, and in `update` we apply it.
-    
-    self.fader = { value = 0 }
     task.tween(self.fader, { value = 1 }, ms or 1000, ease.easeOutCubic)(function()
+        if self.from then
+            self.from:setVolume(0)
+            self.from:stop()
+        end
+        if self.to then
+            self.to:setVolume(self.musicVolume)
+        end
         self.fader = nil
+        print("[Audio]: Crossfade done")
     end)
 end