Fix: Resolve crash on startup due to ProGuard/Gson TypeToken issue

- Added necessary ProGuard rules to keep HighScore class, generic signatures, and annotations.

- Fixed bug where music started on title screen instead of game start.

- Fixed bug where session stats were blank on game over screen by ensuring stats are displayed correctly after high score entry.

- Fixed bug where game music did not restart after playing again.

app/proguard-rules.pro

@@ -1,10 +1,41 @@
 # Add project specific ProGuard rules here.
-# You can control the set of applied configuration files using the
-# proguardFiles setting in build.gradle.
+# By default, the flags in this file are appended to flags specified
+# in /Users/coreyclark/Library/Android/sdk/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
 #
 # For more details, see
 #   http://developer.android.com/guide/developing/tools/proguard.html
 
+# Add any project specific keep options here:
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number table for debugging exceptions.
+#-keepattributes SourceFile,LineNumberTable
+
+# Keep rule for Gson serialization of HighScore data class
+-keep class com.pixelmintdrop.model.HighScore { *; }
+-keepclassmembers class com.pixelmintdrop.model.HighScore { *; }
+
+# Keep generic signatures for Gson TypeToken
+-keepattributes Signature
+
+# Keep annotations used by Gson (e.g., @SerializedName, @Expose)
+-keepattributes *Annotation*
+
+# Keep the anonymous inner class generated for the TypeToken in HighScoreManager
+-keep class com.pixelmintdrop.model.HighScoreManager$* { *; }
+
+# Keep Gson TypeToken related classes
+-keep class com.google.gson.reflect.TypeToken { *; }
+-keep class com.google.gson.reflect.** { *; }
+
 # Keep models intact
 -keep class com.pixelmintdrop.model.** { *; }