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/data/FolderBookMetadata.kt

@@ -19,7 +19,8 @@ data class FolderBookMetadata(
     val bookmarksJson: String?,
     val locatorBlockIndex: Int?,
     val locatorCharOffset: Int?,
-    val customName: String?
+    val customName: String?,
+    val highlightsJson: String?
 ) {
     fun toJsonString(): String {
         val json = JSONObject()
@@ -38,6 +39,7 @@ data class FolderBookMetadata(
         json.put("locatorBlockIndex", locatorBlockIndex ?: -1)
         json.put("locatorCharOffset", locatorCharOffset ?: -1)
         json.put("customName", customName)
+        json.put("highlightsJson", highlightsJson)
         return json.toString()
     }
 
@@ -69,7 +71,8 @@ data class FolderBookMetadata(
                 bookmarksJson = json.optStringNull("bookmarksJson"),
                 locatorBlockIndex = json.optIntNull("locatorBlockIndex"),
                 locatorCharOffset = json.optIntNull("locatorCharOffset"),
-                customName = json.optStringNull("customName")
+                customName = json.optStringNull("customName"),
+                highlightsJson = json.optStringNull("highlightsJson")
             )
         }
     }
@@ -97,6 +100,7 @@ fun FolderBookMetadata.toRecentFileItem(uriString: String?, coverPath: String?,
         isDeleted = false,
         bookmarksJson = this.bookmarksJson,
         sourceFolderUri = sourceFolderUri,
-        customName = this.customName
+        customName = this.customName,
+        highlightsJson = this.highlightsJson
     )
 }