fix(log): 截断超长配置值避免日志文件膨胀

config 加载日志会原样打印 tracker 列表与 base64 缓存（如 ed2k_nodes_dat_cache ~8KB）。Dart 侧配置值压平换行并截断到 120 字符；Rust 侧 bt_config 从 Debug 全量输出改为字段摘要（tracker 只打行数）。

Author: zerx-lab

lib/src/models/settings_provider.dart

@@ -981,11 +981,20 @@ class SettingsProvider extends ChangeNotifier {
     }
   }
 
+  /// 日志用值截断：压平换行并限制长度，避免 tracker 列表 / base64 缓存
+  /// （如 ed2k_nodes_dat_cache ~8KB）把日志文件撑爆。
+  static String _truncateForLog(String value) {
+    const maxLen = 120;
+    final flat = value.replaceAll('\r\n', r'\n').replaceAll('\n', r'\n');
+    if (flat.length <= maxLen) return flat;
+    return '${flat.substring(0, maxLen)}…(${value.length} chars)';
+  }
+
   void _onConfigLoaded(RustSignalPack<ConfigLoaded> pack) {
     final entries = pack.message.entries;
     logInfo('Settings', '_onConfigLoaded: ${entries.length} entries');
     for (final entry in entries) {
-      logInfo('Settings', '  config: ${entry.key}=${entry.value}');
+      logInfo('Settings', '  config: ${entry.key}=${_truncateForLog(entry.value)}');
       switch (entry.key) {
         case 'default_save_dir':
           _defaultSaveDir = entry.value;

native/hub/src/actors/download_actor.rs

@@ -287,11 +287,17 @@ pub async fn run(db_dir: PathBuf) {
         bt_config.custom_trackers = defaults;
     }
     log_info!(
-        "[actor] init config: max_concurrent={}, speed_limit_bps={}, save_dir={}, bt_config={:?}",
+        "[actor] init config: max_concurrent={}, speed_limit_bps={}, save_dir={}, \
+         bt: dht={}, upnp={}, ports={}-{}, custom_trackers={} lines, subscription_trackers={} lines",
         max_concurrent,
         speed_limit_bps,
         save_dir,
-        bt_config,
+        bt_config.enable_dht,
+        bt_config.enable_upnp,
+        bt_config.port_start,
+        bt_config.port_end,
+        bt_config.custom_trackers.lines().count(),
+        bt_config.subscription_trackers.lines().count(),
     );
 
     let app_data_dir = db_dir.to_string_lossy().into_owned();