many improvements and prototype launcher image

composeApp/src/jvmMain/kotlin/net/sergeych/toread/BookPlatform.jvm.kt

@@ -255,9 +255,24 @@ actual suspend fun saveLibraryReadingPosition(fileId: String, position: ReadingP
     }
 }
 
+actual suspend fun clearLibraryReadingPosition(fileId: String) = withContext(Dispatchers.IO) {
+    openLibraryDatabase().useLibrary { db ->
+        val file = db.files.get(fileId) ?: return@useLibrary
+        val clusterId = file.bodyClusterId ?: return@useLibrary
+        db.readingStates.deleteForBodyCluster(clusterId)
+    }
+    Unit
+}
+
 actual suspend fun markLibraryReadingStatus(fileId: String, status: BookReadingStatus): Boolean = withContext(Dispatchers.IO) {
     openLibraryDatabase().useLibrary { db ->
-        db.files.updateReadingStatus(fileId, status)
+        db.transaction {
+            if (status == BookReadingStatus.NEW) {
+                val file = files.get(fileId) ?: return@transaction false
+                file.bodyClusterId?.let { readingStates.deleteForBodyCluster(it) }
+            }
+            files.updateReadingStatus(fileId, status)
+        }
     }
 }