General fixes (#19)

* fix OOM crash by refactoring EpubImage to use lazy loading

- Removed raw image ByteArray from EpubImage data class to prevent OutOfMemoryErrors on large books.
- Updated EpubParser and MobiParser to only store image paths in the EpubBook object.
- Images are now loaded on-demand from disk via file URIs in WebView and Coil, reducing initial heap allocation.

* fix(tts): resolve OutOfMemoryError by removing large strings from state bundle

- Removed 'currentText' from the TtsState bundle inside MediaSession custom layout.
- Updated TtsController to retrieve the current text chunk via MediaItem metadata.
- This prevents heap exhaustion caused by high-frequency serialization of large text strings during word tracking and polling updates.

app/src/main/java/com/aryan/reader/tts/TtsController.kt

@@ -236,7 +236,7 @@ class TtsController(context: Context) : Player.Listener {
                 isPlaying = controller.isPlaying,
                 isLoading = isLoading,
                 currentText = if (isPlaybackActive) {
-                    currentTextFromMediaItem ?: customState.getString("currentText")
+                    currentTextFromMediaItem
                 } else {
                     if (isLoading) currentState.currentText else null
                 },

app/src/main/java/com/aryan/reader/tts/TtsPlaybackManager.kt

@@ -615,7 +615,6 @@ class TtsPlaybackManager(
     private fun createStateButton(state: TtsState): CommandButton {
         val bundle = Bundle().apply {
             putBoolean("isLoading", state.isLoading)
-            putString("currentText", state.currentText)
             putString("errorMessage", state.errorMessage)
             putString("speakerId", state.speakerId)
             putBoolean("sessionEndedByStop", state.sessionEndedByStop)