feat(app-iced): M109 CONTENTDL —— 内容库页（整合包/Mod/资源包/光影）

用户令「下载页只负责下载整合包和Mod/光影」：新开一页做**内容发现与装入**，
检索走 Modrinth（优先，无需 key）/ CurseForge（`ULL_CF_API_KEY` 环境变量，日志只打
set/unset），装入走 core 的下载引擎真下到实例目录，进度/取消/失败复用下载页那块安装面板。

- **入口（B1）**：`Route::Content` 是新顶层路由，但 `Route::nav()` 复用 `NavSection::Download`
  ——导航轨仍五项，页头右上是「版本管理 | 内容库」一级切换（版本管理页也加了同一个切换，
  否则内容库只有 `ULL_START_ROUTE` 能到）
- **页内四条一级侧栏**（`pages/content/layout.rs` 四档几何：992/856/648 三个门槛都是
  「Σ栏宽 + 间距」算出来的）：整合包 / Mod / 资源包 / 光影；标签栏 200（`Resource packs`
  比 M107 的版本类型名长，140 会切字，已登记偏离）
- **筛选**：关键词（草稿 + 显式「搜索」按钮，不逐字打网络）、来源、游戏版本、加载器
  （Fabric/Forge/NeoForge/Quilt）、排序；**分页**（「加载更多」）而不是无限滚动——快照只有一个槽、
  翻页要看得见、状态要可截图复现
- **四态**：加载 / 空 / 失败 / 有数据 + 「没有更多了」；筛选条在任何状态下都在（加载中藏筛选条
  等于把入口收走）
- **一键装入**：`Content::blockers()` 是纯函数——版本不匹配、加载器不匹配、没有目标实例、
  整合包缺管线**四条原因逐条**给出，按钮点之前就禁用；判定与画法分开（model/tests 直接钉）
- **整合包今天不可装**：`ContentKind::Modpack.dir()` 是 `None`，UI 禁用 + 说明，host 侧再挡
  一次（绕过 UI 也只会回一条 Failed）。真流程是 M111 的导入管线
- **零 UI 网络**：`presenter/host/addon.rs` + `addon/{sources,http,install}.rs`；无 header 的请求走
  core 的 `download_bytes`（信号量限流 + 健康度 + 退避全现成），带 `X-API-KEY` 的只有 CF 一条，
  自带 429/5xx 退避（优先吃 `Retry-After`，封顶 30s）；密钥不进 DTO/日志/仓库
- 文案 41 条中英进 `crates/i18n`（新域接在装配链末尾 ⇒ `Key::ALL` 与金表只追加）
- 演示数据 `ContentHit → Hit::of` 与产品路径同源（格式化不会两套），`ULL_CONTENT_KIND` /
  `ULL_CONTENT_STATE` 供出图矩阵选类型与状态

取证：`DevDocs/artifacts/m109/`（10 张：四类内容 × 浅/深 + 搜索无结果 + 加载器不兼容禁用）

门禁：fmt ✓ / clippy `-D warnings`（三 crate）✓ / app-iced 450+6、presenter 170、i18n 24 全绿；
`cargo tree` 两条零 UI 门禁仍空；全部改动文件 ≤400 行。

crates/i18n/src/catalog.rs

@@ -113,6 +113,7 @@ macro_rules! finish {
 }
 
 mod agent;
+mod content;
 mod core_text;
 mod download;
 mod font;
@@ -131,6 +132,7 @@ mod golden;
 mod tests;
 
 use agent::agent_entries;
+use content::content_entries;
 use core_text::core_text_entries;
 use download::{download_entries, version_entries};
 use font::font_entries;
@@ -167,6 +169,9 @@ nav_entries! {
     // `general_entries` 已经在 main 上占了链尾，所以本域排在它们**之后**：
     // `Key::ALL` 顺序 = 金表顺序 = 先 main 的全部域，再 version。
     version_entries,
+    // M109：内容库页。与 M107 同一条纪律——本域排在 main 已占住的链尾**之后**，
+    // 于是 `Key::ALL` 顺序 = 金表顺序 = 先 main 的全部域，再 version，最后 content。
+    content_entries,
     finish,
     {}
 }

crates/i18n/src/catalog/content.rs

@@ -0,0 +1,86 @@
+//! 内容库文案（M109 `CONTENTDL`）。
+//!
+//! 一句话一个 key：带变量的句子用 `{name}`，页面只做 [`crate::Catalog::render`]，不拼片段。
+//!
+//! ## 三条口径
+//!
+//! 1. **只说能做的事**：整合包那条写的是「要等导入管线」，不是「稍后自动支持」；
+//! 2. **站名也进词表**：`Modrinth` / `CurseForge` 的**中文译文必须与英文不同**
+//!    （`catalog/tests.rs` 的 `chinese_catalog_is_actually_chinese` 会红），所以中文写成「Modrinth 源」；
+//! 3. **禁用态要能解释自己**：`ContentIncompatible*` / `ContentModpackNotReady` 就是禁用按钮旁边那几句话——
+//!    没有它们，禁用就等于「点了没反应」。
+//!
+//! 域文件的形状见 `crate::catalog` 的「域装配」一节。
+
+macro_rules! content_entries {
+    ($next:ident, $($rest:ident,)* { $($acc:tt)* }) => {
+        $next! { $($rest,)* {
+            $($acc)*
+            // --- content library page (M109) ---
+            ContentTitle => ("Content", "内容库"),
+            ContentSubtitle => (
+                "Modpacks, mods, resource packs and shaders",
+                "整合包、Mod、资源包与光影"
+            ),
+            ContentSectionVersions => ("Version management", "版本管理"),
+            ContentSectionContent => ("Content library", "内容库"),
+            ContentKindModpack => ("Modpacks", "整合包"),
+            ContentKindMod => ("Mods", "Mod"),
+            ContentKindResourcepack => ("Resource packs", "资源包"),
+            ContentKindShader => ("Shaders", "光影"),
+            ContentSourceModrinth => ("Modrinth", "Modrinth 源"),
+            ContentSourceCurseforge => ("CurseForge", "CurseForge 源"),
+            ContentSortRelevance => ("Relevance", "相关度"),
+            ContentSortDownloads => ("Downloads", "下载量"),
+            ContentSortNewest => ("Newest", "最新发布"),
+            ContentSortUpdated => ("Recently updated", "最近更新"),
+            ContentSearchPlaceholder => ("Search content…", "搜索内容…"),
+            ContentSearch => ("Search", "搜索"),
+            ContentFilterVersion => ("Game version", "游戏版本"),
+            ContentFilterLoader => ("Loader", "加载器"),
+            ContentFilterAny => ("Any", "不限"),
+            ContentCount => ("{count} results", "{count} 个结果"),
+            ContentLoading => ("Loading content…", "正在加载内容…"),
+            ContentLoadingHint => (
+                "Results come from the network; nothing is cached offline yet.",
+                "结果来自网络，暂时没有离线缓存。"
+            ),
+            ContentEmptyTitle => ("Nothing matched", "没有匹配的内容"),
+            ContentEmptyBody => (
+                "Try another keyword, or clear a filter.",
+                "换个关键词，或清掉一个筛选条件。"
+            ),
+            ContentFailedTitle => ("Could not load content", "内容加载失败"),
+            ContentFailedBody => ("Check the network, then retry.", "检查网络后重试。"),
+            ContentRetry => ("Retry", "重试"),
+            ContentLoadMore => ("Load more", "加载更多"),
+            ContentNoMore => ("No more results", "没有更多了"),
+            ContentDetailEmpty => (
+                "Pick an item to see what it supports.",
+                "选一个项目看它支持什么。"
+            ),
+            ContentDetailDownloads => ("{count} downloads", "下载量 {count}"),
+            ContentDetailUpdated => ("Updated {date}", "更新于 {date}"),
+            ContentDetailLoaders => ("Loaders: {list}", "加载器：{list}"),
+            ContentDetailVersions => ("Game versions: {list}", "游戏版本：{list}"),
+            ContentInstall => ("Install into instance", "装入实例"),
+            ContentTargetInstance => ("Target instance", "目标实例"),
+            ContentNoInstances => ("No instance to install into", "没有可装入的实例"),
+            ContentIncompatibleVersion => (
+                "Needs {version}; this instance runs {actual}",
+                "需要 {version}，该实例运行的是 {actual}"
+            ),
+            ContentIncompatibleLoader => ("Not built for {loader}", "不支持 {loader}"),
+            ContentModpackNotReady => (
+                "Modpack install comes with the M111 import pipeline",
+                "整合包安装要等 M111 的导入管线"
+            ),
+            ContentSourceUnavailable => (
+                "Set ULL_CF_API_KEY to search CurseForge",
+                "要搜 CurseForge 请先设置 ULL_CF_API_KEY"
+            ),
+        } }
+    };
+}
+
+pub(crate) use content_entries;

crates/i18n/src/catalog/golden.rs

@@ -176,4 +176,46 @@ pub(super) const GOLDEN: &[(&str, &str, &str)] = &[
     ("VersionSearchHitsOne", "1 match", "1 个匹配"),
     ("VersionSearchElsewhereTitle", "Found in another type", "在别的类型里找到了"),
     ("VersionSearchElsewhereOne", "1 version matches, but it is in another type.", "有 1 个版本匹配，但它在别的类型里。"),
+    // --- M109 内容库页（同样追加在链尾：`Key::ALL` 顺序 = 金表顺序） ---
+    ("ContentTitle", "Content", "内容库"),
+    ("ContentSubtitle", "Modpacks, mods, resource packs and shaders", "整合包、Mod、资源包与光影"),
+    ("ContentSectionVersions", "Version management", "版本管理"),
+    ("ContentSectionContent", "Content library", "内容库"),
+    ("ContentKindModpack", "Modpacks", "整合包"),
+    ("ContentKindMod", "Mods", "Mod"),
+    ("ContentKindResourcepack", "Resource packs", "资源包"),
+    ("ContentKindShader", "Shaders", "光影"),
+    ("ContentSourceModrinth", "Modrinth", "Modrinth 源"),
+    ("ContentSourceCurseforge", "CurseForge", "CurseForge 源"),
+    ("ContentSortRelevance", "Relevance", "相关度"),
+    ("ContentSortDownloads", "Downloads", "下载量"),
+    ("ContentSortNewest", "Newest", "最新发布"),
+    ("ContentSortUpdated", "Recently updated", "最近更新"),
+    ("ContentSearchPlaceholder", "Search content…", "搜索内容…"),
+    ("ContentSearch", "Search", "搜索"),
+    ("ContentFilterVersion", "Game version", "游戏版本"),
+    ("ContentFilterLoader", "Loader", "加载器"),
+    ("ContentFilterAny", "Any", "不限"),
+    ("ContentCount", "{count} results", "{count} 个结果"),
+    ("ContentLoading", "Loading content…", "正在加载内容…"),
+    ("ContentLoadingHint", "Results come from the network; nothing is cached offline yet.", "结果来自网络，暂时没有离线缓存。"),
+    ("ContentEmptyTitle", "Nothing matched", "没有匹配的内容"),
+    ("ContentEmptyBody", "Try another keyword, or clear a filter.", "换个关键词，或清掉一个筛选条件。"),
+    ("ContentFailedTitle", "Could not load content", "内容加载失败"),
+    ("ContentFailedBody", "Check the network, then retry.", "检查网络后重试。"),
+    ("ContentRetry", "Retry", "重试"),
+    ("ContentLoadMore", "Load more", "加载更多"),
+    ("ContentNoMore", "No more results", "没有更多了"),
+    ("ContentDetailEmpty", "Pick an item to see what it supports.", "选一个项目看它支持什么。"),
+    ("ContentDetailDownloads", "{count} downloads", "下载量 {count}"),
+    ("ContentDetailUpdated", "Updated {date}", "更新于 {date}"),
+    ("ContentDetailLoaders", "Loaders: {list}", "加载器：{list}"),
+    ("ContentDetailVersions", "Game versions: {list}", "游戏版本：{list}"),
+    ("ContentInstall", "Install into instance", "装入实例"),
+    ("ContentTargetInstance", "Target instance", "目标实例"),
+    ("ContentNoInstances", "No instance to install into", "没有可装入的实例"),
+    ("ContentIncompatibleVersion", "Needs {version}; this instance runs {actual}", "需要 {version}，该实例运行的是 {actual}"),
+    ("ContentIncompatibleLoader", "Not built for {loader}", "不支持 {loader}"),
+    ("ContentModpackNotReady", "Modpack install comes with the M111 import pipeline", "整合包安装要等 M111 的导入管线"),
+    ("ContentSourceUnavailable", "Set ULL_CF_API_KEY to search CurseForge", "要搜 CurseForge 请先设置 ULL_CF_API_KEY"),
 ];