feedback7 stats: the local statistics page, ported from PR #323 by @2321Robin as submitted (record store ui/stats.js, viewer screens/stats.js, stats.css, entries on the title / lobby / room screens, 20 tests); golden: unchanged

- public/js/ui/stats.js: one record per finished match in localStorage (sp.pref.stats, envelope {v, records}, at most
  1000, quota shrink of the oldest), content-id dedupe of the lobby's result replay, a MIGRATIONS chain and
  normalizeRecord (defaults for missing fields, unknown fields kept, a newer envelope refused), merge-by-id export /
  import, aggregateStats.
- public/js/screens/stats.js: the viewer (总览 / 策略 / 称号 / 战斗累计 / 最近对局, a row re-views that match's
  settlement), 导出 / 导入 / 清空.
- Applied from the PR's own diff after reading it in full (no network, no new dependency, server untouched); only the
  UI strings of the page are added to the four packs (en from the PR; ja / ko / zh-TW translated for this commit).
- The follow-up commits rework the page (the counting rule for matches left early, storage bounds, the layout).
- Tests: test/ui/stats.test.js 20 / 20; i18n extract 0, check --all --strict clean.

public/i18n/en.json

@@ -1055,5 +1055,46 @@
   "选择「{name}」的朝向": "Choose {name}'s facing",
   "选择朝向": "Choose a facing",
   "朝向：{dir}": "Facing: {dir}",
-  "开发版 · 不稳定，请勿用于公开服务器": "Development build · unstable, not for public servers"
+  "开发版 · 不稳定，请勿用于公开服务器": "Development build · unstable, not for public servers",
+  "统计数据": "Statistics",
+  "统计": "Stats",
+  "对局进行中，暂不能回看历史结算": "A match is running — replays are unavailable right now",
+  "总览": "Overview",
+  "总局数": "Games",
+  "胜场": "Wins",
+  "胜率": "Win rate",
+  "到达隐秘核心": "Hidden Core reached",
+  "通关隐秘核心": "Hidden Core cleared",
+  "最远回合": "Best round",
+  "累计时长": "Time played",
+  "{n} 分": "{n} min",
+  "难度": "Difficulty",
+  "局数": "Games",
+  "隐秘核心通关": "Hidden Core clears",
+  "使用局数": "Used",
+  "通过局数": "Cleared",
+  "通过率": "Clear rate",
+  "称号": "Titles",
+  "战斗累计": "Combat totals",
+  "最近对局": "Recent matches",
+  "时间": "Time",
+  "模式": "Mode",
+  "结果": "Result",
+  "点击查看该局结算": "View this match's settlement",
+  "单人": "Solo",
+  "同盟": "Co-op",
+  "胜": "Win",
+  "负": "Loss",
+  "点击任意一行，回看该局结算。": "Click a row to re-view that match's settlement.",
+  "已导出 {n} 条对局记录": "Exported {n} match records",
+  "已导入 {added} 条记录{tail}": "Imported {added} records{tail}",
+  "（跳过重复 {skipped} 条）": " ({skipped} duplicates skipped)",
+  "没有新记录（全部与现有数据重复）": "Nothing new (everything already exists)",
+  "导入失败：不是有效的统计导出文件": "Import failed: not a valid stats export file",
+  "已清空本机统计数据": "Local stats cleared",
+  "确认清空？": "Clear for sure?",
+  "本机数据 · 仅记录本浏览器中你参与的对局": "Local data · only matches you took part in, in this browser",
+  "检测到更新版本的统计数据，请先升级客户端再查看，以免覆盖数据。": "Stats data from a newer version detected — upgrade the client before viewing, or the data could be overwritten.",
+  "还没有记录 —— 完成一局对局后，这里会开始积累。": "No records yet — finish a match and the page starts filling in.",
+  "未知": "Unknown"
 }