add download preferences

shared/src/commonMain/kotlin/net/newpipe/app/preferences/DownloadPreferences.kt

@@ -0,0 +1,48 @@
+/*
+* SPDX-FileCopyrightText: 2026 NewPipe e.V. <https://newpipe-ev.de>
+* SPDX-License-Identifier: GPL-3.0-or-later
+*/
+
+package net.newpipe.app.preferences
+
+/**
+ * Preference keys, values, and defaults for the Download settings screen.
+ *
+ */
+object DownloadPreferences {
+    const val KEY_STORAGE_ASK = "downloads_storage_ask"
+    const val KEY_STORAGE_USE_SAF = "storage_use_saf"
+    const val KEY_DOWNLOAD_FOLDER_VIDEO = "download_path"
+    const val KEY_DOWNLOAD_FOLDER_AUDIO = "download_path_audio"
+    const val KEY_FILE_CHARSET = "file_rename_charset"
+    const val KEY_REPLACEMENT_CHARACTER = "file_replacement_character"
+    const val KEY_MAXIMUM_RETRIES = "downloads_max_retry"
+    const val KEY_PAUSE_ON_METERED_NETWORK = "cross_network_downloads"
+    const val KEY_LIMIT_QUEUE = "downloads_queue_limit"
+
+    const val CHARSET_LETTERS_AND_DIGITS = "CHARSET_LETTERS_AND_DIGITS"
+    const val CHARSET_MOST_SPECIAL = "CHARSET_MOST_SPECIAL"
+
+    const val DEFAULT_STORAGE_ASK = false
+    const val DEFAULT_STORAGE_USE_SAF = true
+
+    const val DEFAULT_DOWNLOAD_FOLDER = ""
+    const val DEFAULT_FILE_CHARSET = CHARSET_MOST_SPECIAL
+    const val DEFAULT_REPLACEMENT_CHARACTER = "_"
+    const val DEFAULT_MAXIMUM_RETRIES = "3"
+    const val DEFAULT_PAUSE_ON_METERED_NETWORK = false
+    const val DEFAULT_LIMIT_QUEUE = true
+
+    val FILE_CHARSETS = listOf(CHARSET_LETTERS_AND_DIGITS, CHARSET_MOST_SPECIAL)
+
+    const val MAXIMUM_RETRIES_NONE = "0"
+
+    val MAXIMUM_RETRY_COUNTS = listOf(
+        MAXIMUM_RETRIES_NONE, "1", "2", "3", "4", "5", "7", "10", "15"
+    )
+
+    fun normalizedMaximumRetries(storedValue: String): String = when (storedValue.toIntOrNull()) {
+        null -> MAXIMUM_RETRIES_NONE
+        else -> storedValue
+    }
+}