release: v0.2.4 里程碑快照（孤儿提交，无父；树 = dev 68362e5）

本批内容见 CHANGELOG.md 的 0.2.4 段。按 D41 用孤儿快照推 main，保留「公开史只有里程碑」的模型。

crates/core/tests/liteloader/support.rs

@@ -0,0 +1,157 @@
+//! 集成测试公用件：临时游戏目录、离线下载引擎、元数据夹具、父版本清单夹具。
+
+#![allow(dead_code)]
+
+use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+
+use unlucky_core::addon::loader::liteloader::{self, LiteLoaderEntry};
+use unlucky_core::addon::loader::LoaderRelease;
+use unlucky_core::download::backoff::BackoffPolicy;
+use unlucky_core::download::cache::ContentCache;
+use unlucky_core::download::chunked::ChunkedConfig;
+use unlucky_core::download::config::EngineConfig;
+use unlucky_core::download::engine::DownloadEngine;
+use unlucky_core::download::health::HealthRegistry;
+use unlucky_core::download::mirrors::MirrorTable;
+use unlucky_core::download::region::RegionProfile;
+use unlucky_core::game::layout::GameLayout;
+use unlucky_core::game::manifest::VersionJson;
+
+/// 真实响应的裁剪版（见 `tests/liteloader.rs` 文件头的来源说明）。
+pub const VERSION_TABLE: &str = include_str!("fixtures/liteloader-versions.json");
+
+/// 1.12.2-SNAPSHOT 的 maven-metadata（真实响应原样）。
+pub const METADATA_XML: &str = r#"<?xml version="1.0" encoding="UTF-8"?>
+<metadata>
+  <groupId>com.mumfrey</groupId>
+  <artifactId>liteloader</artifactId>
+  <version>1.12.2-SNAPSHOT</version>
+  <versioning>
+    <snapshot>
+      <timestamp>20171128.144431</timestamp>
+      <buildNumber>4</buildNumber>
+    </snapshot>
+    <lastUpdated>20171128144431</lastUpdated>
+  </versioning>
+</metadata>"#;
+
+/// 原版 1.12.2（老式 `minecraftArguments`，与官方清单同形）。
+pub const VANILLA_1122: &str = r#"{
+  "id": "1.12.2",
+  "type": "release",
+  "mainClass": "net.minecraft.client.main.Main",
+  "assets": "1.12",
+  "assetIndex": {"id": "1.12"},
+  "minecraftArguments": "--username ${auth_player_name} --version ${version_name}",
+  "libraries": [
+    {"name": "com.mojang:patchy:1.1", "url": "https://libraries.minecraft.net/"}
+  ]
+}"#;
+
+/// Forge 1.12.2-14.23.5.2860（spec-0 的 version.json：主类 launchwrapper + FMLTweaker）。
+pub const FORGE_1122: &str = r#"{
+  "id": "1.12.2-forge-14.23.5.2860",
+  "inheritsFrom": "1.12.2",
+  "mainClass": "net.minecraft.launchwrapper.Launch",
+  "minecraftArguments": "--tweakClass net.minecraftforge.fml.common.launcher.FMLTweaker",
+  "libraries": [
+    {"name": "net.minecraftforge:forge:1.12.2-14.23.5.2860", "url": "https://maven.minecraftforge.net/"}
+  ]
+}"#;
+
+/// 唯一临时目录守卫（`drop` 时递归删除）。
+pub struct TempDir {
+    path: PathBuf,
+}
+
+impl TempDir {
+    pub fn new(tag: &str) -> Self {
+        static COUNTER: AtomicUsize = AtomicUsize::new(0);
+        let unique = COUNTER.fetch_add(1, Ordering::Relaxed);
+        let stamp = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .map_or(0, |since| since.as_nanos());
+        let path = std::env::temp_dir().join(format!(
+            "ull-liteloader-{tag}-{}-{stamp}-{unique}",
+            std::process::id()
+        ));
+        let _ = std::fs::remove_dir_all(&path);
+        std::fs::create_dir_all(&path).expect("临时目录应可创建");
+        Self { path }
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+impl Drop for TempDir {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_dir_all(&self.path);
+    }
+}
+
+/// 离线引擎：单次尝试、短超时、分块关闭（测试里只用来跑「全部跳过」的执行段）。
+pub fn engine(cache_root: &Path) -> DownloadEngine {
+    let config = EngineConfig {
+        max_attempts_per_source: 1,
+        backoff: BackoffPolicy {
+            base_ms: 1,
+            max_ms: 2,
+            jitter_ratio: 0.0,
+            max_attempts: 1,
+        },
+        connect_timeout: Duration::from_secs(3),
+        read_timeout: Duration::from_secs(3),
+        chunked: ChunkedConfig::disabled(),
+        ..EngineConfig::default()
+    };
+    DownloadEngine::new(
+        config,
+        Arc::new(MirrorTable::builtin()),
+        Arc::new(RegionProfile::direct(0)),
+        Arc::new(HealthRegistry::in_memory()),
+        Arc::new(ContentCache::open(cache_root.join("cache"))),
+    )
+}
+
+/// 解析夹具表里某个原版版本的条目。
+pub fn entries(mc_version: &str) -> Vec<LiteLoaderEntry> {
+    let table = liteloader::parse_versions(VERSION_TABLE).expect("夹具版本表应可解析");
+    table.get(mc_version).cloned().unwrap_or_default()
+}
+
+/// 取 1.12.2 的 SNAPSHOT 条目并合成 release（父版本由调用方给）。
+pub fn liteloader_release(parent_version_id: &str) -> LoaderRelease {
+    let entries = entries("1.12.2");
+    let entry = liteloader::default_entry(&entries).expect("1.12.2 应有一条版本");
+    let url = liteloader::snapshot_artifact_url(entry, METADATA_XML).expect("快照直链");
+    liteloader::build_release("1.12.2", parent_version_id, entry, &url).expect("合成清单")
+}
+
+/// 把一份版本 JSON 写进 `versions/<id>/<id>.json`（模拟「父版本已装好」）。
+pub fn put_version(layout: &GameLayout, id: &str, json: &str) {
+    let path = layout.version_json(id);
+    std::fs::create_dir_all(path.parent().expect("版本目录")).expect("建版本目录");
+    std::fs::write(&path, json).expect("写版本 JSON");
+}
+
+/// 读盘上的版本 JSON。
+pub fn read_version(layout: &GameLayout, id: &str) -> VersionJson {
+    let path = layout.version_json(id);
+    let text = std::fs::read_to_string(&path)
+        .unwrap_or_else(|error| panic!("读不到 {}：{error}", path.display()));
+    VersionJson::from_json_str(&text).expect("版本 JSON 应可解析")
+}
+
+/// 按计划把每个待下文件写成占位字节（`execute` 的跳过判据 = 无 sha1 且存在即信）。
+pub fn prefill(plan: &unlucky_core::game::install::InstallPlan) -> usize {
+    for file in &plan.files {
+        std::fs::create_dir_all(file.dest.parent().expect("文件父目录")).expect("建库目录");
+        std::fs::write(&file.dest, b"placeholder").expect("写占位文件");
+    }
+    plan.files.len()
+}