General improvments (#114)

* Add "Keep Screen On" feature to PDF and Epub readers.

* Add `rawLibraryFiles` to `MainViewModel` and improve file path resolution in `SharedComposables`.

Specifically:
- Updated `MainViewModel` state and UI logic to track and provide unfiltered library files.
- Enhanced file path formatting in `SharedComposables` to better handle Document, Tree, and primary storage URIs.
- Added scrollable support for long text values in `DetailItem` composable.
- Passed `rawLibraryFiles` to `FolderSyncScreen` to ensure sync logic uses the base file list.

* Update info bar background and text colors in EpubReaderScreen to match the selected theme.

* Prevent accidental UI bar toggles immediately after scrolling in EPUB vertical mode.

* feat: implement EPUB highlights sync and legacy migration

- Implement Cloud and Local Folder sync for EPUB highlights.
- Add highlight JSON serialization/deserialization helpers in EpubReaderAnnotations.
- Implement automatic migration of highlights from SharedPreferences to the Database on book open.
- Add cleanup logic to remove legacy SharedPreferences data after successful DB migration.
- Update RecentFilesRepository to trigger local folder metadata sync when highlights are modified.
- Update FolderSyncWorker to pull highlights and custom names from linked folder metadata.

* Update intent filters

app/src/main/java/com/aryan/reader/epubreader/EpubReaderControls.kt

@@ -142,6 +142,8 @@ fun EpubReaderTopBar(
     volumeScrollEnabled: Boolean,
     isPageTurnAnimationEnabled: Boolean,
     onNavigateBack: () -> Unit,
+    isKeepScreenOn: Boolean,
+    onToggleKeepScreenOn: (Boolean) -> Unit,
     onCloseSearch: () -> Unit,
     onChangeRenderMode: (RenderMode) -> Unit,
     onToggleBookmark: () -> Unit,
@@ -334,6 +336,16 @@ fun EpubReaderTopBar(
                             )
                             HorizontalDivider()
 
+                            DropdownMenuItem(
+                                text = { Text("Keep Screen On") },
+                                onClick = {
+                                    onToggleKeepScreenOn(!isKeepScreenOn)
+                                    showMoreMenu = false
+                                },
+                                trailingIcon = { if (isKeepScreenOn) Icon(Icons.Default.Check, contentDescription = "Enabled") }
+                            )
+                            HorizontalDivider()
+
                             DropdownMenuItem(
                                 text = { Text("Auto Scroll") },
                                 enabled = !isTtsActive && currentRenderMode == RenderMode.VERTICAL_SCROLL,