feat(m188): launcher.log 早落盘 + 会话日志搬到 logs/game（旧家只读兼容）

用户投诉原话：「我们的启动日志放在哪？…他找半天没找到崩溃日志」「只有一个安装日志」。

启动器运行日志（.ULL/logs/launcher.log）
- presenter 构造 HostEnv 时就登记日志目录：启动早期缓冲的 200 行（[probe]/[font]/[theme]）
  当场刷盘，不再是「只有开过一局游戏才有日志」。
- app/** 里所有 eprintln! 诊断改走 app::diag::diag!（stderr + 文件双写，行首 [tag] 即 scope），
  含 boot/boot::fallback/state/update 各线。
- boot 那一拍补一行后端事实（request/effective/fallback）。
- 滚动上限（1 MiB → launcher.1.log，只留一份）写进 README 与 docs/logs-location.md。

会话日志搬家：data/agent/sessions → logs
- LauncherLayout: sessions_root()/game_logs() 新增，agent_sessions() 降级为只读兼容。
- host/logs 与 cli/commands/sessions 两个根合并（同 id 新根优先），event_path 回落旧家。
- 不搬不删；日志目录写一份 session-log-location.json 记录（moved=0, policy=read-only-compat）。

入口与文案
- 设置页「通用」新增「日志文件夹」行：路径 + 打开目录 + 复制路径（i18n 中英）。
- 日志页页头的「打开目录」不再是占位：走 M187 的 open_dir，失败文本带路径并送进剪贴板。
- README.md / README.zh-CN.md 新增「日志在哪」章节（含 crash-reports 只在游戏走到那一步才有），
  docs/logs-location.md 给出上限、双写判据、迁移策略与没验的部分。

守门（每条都有变异证明，见报告）
- 旧家会话仍列得出/打不开 ⇒ 只读新根变红；新会话写 logs/game ⇒ 只读旧根、写回旧家都变红。
- launcher.log 滚动 ⇒ 干掉 rename 变红。
- 打开日志文件夹指向真实目录 ⇒ 换成 cache/ 或去掉 create_dir_all 都变红。
- 日志根随三模式变化 ⇒ 把 HostEnv::logs_dir 写死成便携落点变红。

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

@@ -24,6 +24,10 @@ pub(super) const ROWS: &[(&str, &str, &str)] = &[
     ("FontCjkReady", "Chinese font ready: {family}", "中文字体已就绪：{family}"),
     ("SettingsLanguage", "Language", "界面语言"),
     ("SettingsLanguageHint", "Switches the interface language. Chinese text needs a Chinese font.", "切换界面语言。显示中文需要中文字体。"),
+    ("SettingsLogsFolder", "Log folder", "日志文件夹"),
+    ("SettingsLogsFolderHint", "What explains a crash lives here: the launcher's own runtime log (launcher.log, rolled over at 1 MiB with one old copy kept) and one jsonl per game session under logs/game/. Sessions from older versions (data/agent/sessions) are still read, not moved.", "解释一次崩溃要看的东西都在这：启动器自己的运行日志（launcher.log，满 1 MiB 滚动一次、只留一份旧档）与每次游戏会话的 jsonl（logs/game/）。旧版本留下的会话（data/agent/sessions）仍然读得出来，不会被搬动。"),
+    ("SettingsLogsCopy", "Copy path", "复制路径"),
+    ("SettingsLogsUnknown", "Data directory not resolved — restart the launcher from its own folder", "数据根没解析出来——从启动器所在目录重新启动试试"),
     ("SettingsAppearanceCorner", "Window corners", "窗口圆角"),
     ("SettingsAppearanceCornerSystem", "Follow system", "跟随系统"),
     ("SettingsAppearanceCornerSquare", "Square", "直角"),
@@ -389,9 +393,4 @@ pub(super) const ROWS: &[(&str, &str, &str)] = &[
     ("PackNoDialog", "This build has no system file picker: drag the file in, or paste its path below.", "本版没有系统文件选择框：请把文件拖进来，或在下面粘贴路径。"),
     ("PackPathLabel", "Pack path", "整合包路径"),
     ("PackPathPlaceholder", "D:\\packs\\Better MC.mrpack", "D:\\整合包\\更好的MC.mrpack"),
-    ("PackImportAction", "Import", "导入"),
-    ("PackCancel", "Cancel import", "取消导入"),
-    ("PackDismiss", "Dismiss", "关闭"),
-    ("PackTargetLabel", "Install into", "装到实例"),
-    ("PackTargetNew", "New instance", "新建实例"),
 ];

crates/i18n/src/catalog/golden/tail2.rs

@@ -4,6 +4,11 @@
 //! 拼装见 `golden.rs` 的 [`super::rows`]。
 
 pub(super) const ROWS: &[(&str, &str, &str)] = &[
+    ("PackImportAction", "Import", "导入"),
+    ("PackCancel", "Cancel import", "取消导入"),
+    ("PackDismiss", "Dismiss", "关闭"),
+    ("PackTargetLabel", "Install into", "装到实例"),
+    ("PackTargetNew", "New instance", "新建实例"),
     ("PackInstanceName", "Instance name", "实例名"),
     ("PackStageLine", "Step {index}/{total} · {stage}", "步骤 {index}/{total} · {stage}"),
     ("PackStageProbe", "Reading the manifest", "读取清单"),

crates/i18n/src/catalog/settings/general.rs

@@ -12,6 +12,17 @@ macro_rules! settings_general_entries {
                 "Switches the interface language. Chinese text needs a Chinese font.",
                 "切换界面语言。显示中文需要中文字体。"
             ),
+            // ── 日志文件夹（M188：用户投诉「找不到崩溃日志」的直接落点）
+            SettingsLogsFolder => ("Log folder", "日志文件夹"),
+            SettingsLogsFolderHint => (
+                "What explains a crash lives here: the launcher's own runtime log (launcher.log, rolled over at 1 MiB with one old copy kept) and one jsonl per game session under logs/game/. Sessions from older versions (data/agent/sessions) are still read, not moved.",
+                "解释一次崩溃要看的东西都在这：启动器自己的运行日志（launcher.log，满 1 MiB 滚动一次、只留一份旧档）与每次游戏会话的 jsonl（logs/game/）。旧版本留下的会话（data/agent/sessions）仍然读得出来，不会被搬动。"
+            ),
+            SettingsLogsCopy => ("Copy path", "复制路径"),
+            SettingsLogsUnknown => (
+                "Data directory not resolved — restart the launcher from its own folder",
+                "数据根没解析出来——从启动器所在目录重新启动试试"
+            ),
         } }
     };
 }