feat(presenter): 多根发现（配置根 + 官方启动器标准位置），实例按自己的根解析存档/模组/启动（M274）

crates/presenter/src/host/launch.rs

@@ -63,7 +63,10 @@ pub fn build_request(
     target: &LaunchTarget,
 ) -> Result<(LaunchRequest, Vec<String>), LaunchFailureView> {
     let version_id = target.version_id.clone();
-    let manifest_path = env.game.version_json(&version_id);
+    // **这个实例自己的根**（M274）：官方根 / 另一个 `.minecraft` 里的版本，清单、库、natives、
+    // assets 全在它自己那个根下。拿 `env.game` 去读会读空（甚至读到同名的另一个版本）。
+    let game = super::game::game_for(env, &target.id);
+    let manifest_path = game.version_json(&version_id);
     let text = std::fs::read_to_string(&manifest_path).map_err(|error| {
         LaunchFailureView::new(
             LaunchFailureStage::VersionManifest,
@@ -77,7 +80,7 @@ pub fn build_request(
         )
     })?;
     let source = |id: &str| -> Option<VersionJson> {
-        std::fs::read_to_string(env.game.version_json(id))
+        std::fs::read_to_string(game.version_json(id))
             .ok()
             .and_then(|text| VersionJson::from_json_str(&text).ok())
     };
@@ -121,22 +124,22 @@ pub fn build_request(
             }
         };
         let path = if library.is_local() {
-            env.game.version_library(&version_id, &coordinate)
+            game.version_library(&version_id, &coordinate)
         } else {
-            env.game.library(&coordinate)
+            game.library(&coordinate)
         };
         libraries.push(LibraryInput::new(path, name));
     }
     let natives = unlucky_core::launch::natives::collect(
-        &env.game,
+        &game,
         &version_id,
         resolved.libraries.as_deref().unwrap_or_default(),
         &environment,
     );
 
-    let game_dir = run_dir(env, target)?;
+    let game_dir = run_dir(env, &game, target)?;
     let jar_id = resolved.jar.clone().unwrap_or_else(|| version_id.clone());
-    let assets_root = env.game.assets_dir();
+    let assets_root = game.assets_dir();
     let assets_index = resolved
         .assets
         .clone()
@@ -145,7 +148,7 @@ pub fn build_request(
     // `26w14a-fabric-0.16.5` 这种 id 在 `GameVersion::is_weekly_snapshot`（6 字符形态）上判不出来，
     // 周快照的 `--graphicsBackend` 会在拼装链里被静默跳过——而详情页的门槛
     // （`host::launch_args::backend_gate`）与 CLI 用的都是根版本，两边必须同一口径。
-    let (mc_version, _) = super::game::describe_version(env, &version_id);
+    let (mc_version, _) = super::game::describe_version(&game, &version_id);
     let snapshot = SnapshotInput {
         version_id: &version_id,
         version_name: Some(&target.name),
@@ -157,11 +160,11 @@ pub fn build_request(
         legacy_arguments: resolved.minecraft_arguments.as_deref(),
         libraries: &libraries,
         natives: &natives,
-        primary_jar: env.game.version_jar(&jar_id),
+        primary_jar: game.version_jar(&jar_id),
         game_dir,
         assets_index: assets_index.as_deref(),
-        natives_dir: env.game.natives_dir(&version_id),
-        library_dir: env.game.libraries_dir(),
+        natives_dir: game.natives_dir(&version_id),
+        library_dir: game.libraries_dir(),
         assets_root: assets_root.clone(),
         game_assets: assets_root,
     };
@@ -197,18 +200,22 @@ pub fn build_request(
 ///
 /// 基底档对自动发现的实例是「盘上有没有痕迹」，对其它实例就是全局 `instances.mode`——
 /// 于是这里不需要知道实例是从哪来的，只有一处判据。
-fn run_dir(env: &HostEnv, target: &LaunchTarget) -> Result<PathBuf, LaunchFailureView> {
-    let base = super::game::base_mode(env, &target.id, &target.version_id);
+fn run_dir(
+    env: &HostEnv,
+    game: &unlucky_core::game::GameLayout,
+    target: &LaunchTarget,
+) -> Result<PathBuf, LaunchFailureView> {
+    let base = super::game::base_mode(env, game, &target.id, &target.version_id);
     let config = read_instance_config(&env.layout, &target.id).map_err(|error| {
         LaunchFailureView::new(LaunchFailureStage::InstanceConfig, error.to_string())
     })?;
-    let derivation = derive_game_dir(&env.game, &target.version_id, base, config.as_ref(), None)
+    let derivation = derive_game_dir(game, &target.version_id, base, config.as_ref(), None)
         .map_err(|error| {
             LaunchFailureView::new(LaunchFailureStage::Isolation, error.to_string())
         })?;
     if let Some(mut config) = config {
         let at = format_rfc3339_millis(now());
-        if observe_mode(&mut config, &env.game, &at, derivation.isolation).unwrap_or(false) {
+        if observe_mode(&mut config, game, &at, derivation.isolation).unwrap_or(false) {
             let _ =
                 unlucky_core::game::install::instance::write_instance_config(&env.layout, &config);
         }
@@ -227,11 +234,14 @@ pub fn start(env: HostEnv, tx: JobSender, target: LaunchTarget) {
         let logs_dir = env.layout.logs();
         launcher_log::set_dir(&logs_dir);
         let started_at = std::time::SystemTime::now();
+        // 崩溃报告里的「游戏目录」必须是**这个实例自己那个根**（M274）：官方根里的实例崩了，
+        // 报告却写着 ULL 便携根的路径，等于把排障指到别人的目录上。
+        let game = super::game::game_for(&env, &target.id);
         let mut report = ReportContext::new(
             &target.id,
             &target.name,
             &target.version_id,
-            &env.data.game_home,
+            game.root(),
             &logs_dir,
             started_at,
             unlucky_core::platform::os_info::current().summary_line(),
@@ -261,7 +271,7 @@ pub fn start(env: HostEnv, tx: JobSender, target: LaunchTarget) {
             }
         };
         report.run_dir = request.dirs.game_dir.clone();
-        report.version_json = Some(env.game.version_json(&target.version_id));
+        report.version_json = Some(game.version_json(&target.version_id));
         report.java = launcher_log::java_label(&request.java.binary, request.java.major);
         for warning in &warnings {
             let _ = tx.send(HostTask::Notice(Box::new(crate::dto::NoticeView::new(