feat(app-iced): 下载页在选 LiteLoader 时给中性说明（GUI 只叠原版、Forge 组合走 CLI）

新增 Key::DownloadOptionsLiteLoaderVanillaOnly（中英各一句，不含花括号占位符）；
金表按 Key::ALL 的真实位置插入（DownloadOptionsNeedsAtLeast 之后、DownloadCancelled 之前），
只加新键不重排旧键。说明走 OptionsView 的新字段 note，不塞 problem（那是错误色 + 禁用确认）。

crates/i18n/src/catalog/download.rs

@@ -99,6 +99,12 @@ macro_rules! download_entries {
                 "{loader} needs Minecraft {min} or newer",
                 "{loader} 需要 Minecraft {min} 或更新"
             ),
+            // M222：下载页只做「原版 + 加载器」一层，Forge 父链只有命令行能走。中性说明，
+            // 不是错误（不禁用确认键、不套错误色）——所以它不走 `problem` 那条通道。
+            DownloadOptionsLiteLoaderVanillaOnly => (
+                "LiteLoader stacks on vanilla only — for Forge, run: ull install <forge id> --loader liteloader",
+                "LiteLoader 只叠在原版上 —— 要叠 Forge 请运行：ull install <Forge 版本 id> --loader liteloader"
+            ),
             DownloadCancelled => (
                 "Install cancelled — finished files are kept, the instance was not created",
                 "安装已取消 —— 已下好的文件保留，实例未登记"

crates/i18n/src/catalog/golden/tail_ai.rs

@@ -106,6 +106,7 @@ pub(super) const ROWS: &[(&str, &str, &str)] = &[
     ("DownloadOptionsInstanceNameHint", "Empty = use the version id", "留空就用版本号"),
     ("DownloadOptionsIncompatible", "{loader} has no builds for {version}", "{loader} 没有适配 {version} 的构建"),
     ("DownloadOptionsNeedsAtLeast", "{loader} needs Minecraft {min} or newer", "{loader} 需要 Minecraft {min} 或更新"),
+    ("DownloadOptionsLiteLoaderVanillaOnly", "LiteLoader stacks on vanilla only — for Forge, run: ull install <forge id> --loader liteloader", "LiteLoader 只叠在原版上 —— 要叠 Forge 请运行：ull install <Forge 版本 id> --loader liteloader"),
     ("DownloadCancelled", "Install cancelled — finished files are kept, the instance was not created", "安装已取消 —— 已下好的文件保留，实例未登记"),
     ("LogsSubtitleIdle", "Nothing is running right now", "当前没有运行中的实例"),
     ("LogsStatus", "{instance} · {when} · {outcome}", "{instance}｜{when}｜{outcome}"),