refactor: 高内聚低耦合 - 配置集中化与 i18n 统一

结构优化：
- 新增 mobile-game/config.js：集中模块静态配置（资源路径、排行榜端点、
  hero meta、子标签页定义），消除散落在各组件的硬编码
- 新增 composables/useLocale.js：共享语言辅助(t/isZh/pick)，
  消除 6 个组件各自重复定义的 L() helper
- 文案全部迁入 i18n locale（mobileGame 命名空间），消除模板内联 L('中','英')
- 数据文件 versions.js 去除 {zh,en} 对象，文案改由 i18n 键(tracks/versions)取
- 各组件改为读 config + t()，不再直接 useI18n，降低与 i18n 实现的耦合

headless 验证：中文(hero/meta/team/timeline/3D置顶) + 英文切换 + 切回中文 全通过

src/i18n/locales/en.js

@@ -2,19 +2,96 @@
 // 只看中文的访客不会下载此文件。
 export default {
   app: {
-    title: 'Zikai',
-    nav: {
-      projects: 'Projects',
-      language: 'Language'
-    }
+    title: 'Zikai'
   },
   common: {
     loading: 'Loading…',
-    comingSoon: 'Coming soon',
-    notAvailable: 'Not available',
-    backToTop: 'Back to top'
+    notAvailable: 'Not available'
   },
   tabs: {
     mobileGame: 'Mobile Game Project'
+  },
+  mobileGame: {
+    hero: {
+      title: 'Mobile Game Project',
+      desc: 'A cross-semester Unity mobile-game capstone: 448 built the game (WebGL + Android APK), 449 built the showcase site and player leaderboard. Iterated across versions, from a character controller to a gyroscope-controlled 3D rolling-ball game, with ML-Agents reinforcement-learning experiments.'
+    },
+    meta: {
+      course: 'Miami University · Capstone 448 / 449',
+      stack: 'Stack',
+      stackValue: 'Unity · C# · WebGL · Android · PHP',
+      period: 'Period',
+      periodValue: '2022'
+    },
+    overview: {
+      label: 'Overview',
+      title: 'From character controller to gyro ball',
+      p1: 'The project spans courses 448 and 449. 448 built the game with Unity, producing browser-playable WebGL builds and installable Android APKs; 449 built the showcase site and a PHP+MySQL player leaderboard. The game evolved along several parallel lines, from 2D character controllers and platformers, ultimately shifting to a gyroscope-controlled 3D rolling ball, with ML-Agents reinforcement-learning experiments.',
+      p2: 'Gameplay iterated across versions: early builds were keyboard-controlled 2D character controllers with health/power stats; the final version became a gyroscope-tilt 3D rolling-ball game with falling snowflake bricks and bouncing yellow bricks.'
+    },
+    subtabs: {
+      team: 'Team · Leaderboard',
+      iterations: 'Iterations',
+      experiment: 'Experiment'
+    },
+    team: {
+      label: 'Team',
+      title: 'Members'
+    },
+    leaderboard: {
+      label: 'Leaderboard',
+      title: 'Top 30 Scores',
+      colRank: '#',
+      colName: 'Name',
+      colScore: 'Score',
+      noScores: 'No scores yet',
+      error: 'Leaderboard service unavailable'
+    },
+    iterations: {
+      label: 'Version History',
+      title: 'Iteration Record',
+      colControls: 'Controls',
+      colNote: 'Note',
+      colUnity: 'Unity',
+      playWebgl: 'Play WebGL',
+      downloadApk: 'Download APK',
+      pivotText: 'Earlier parallel lines: 2D'
+    },
+    experiment: {
+      label: 'Experiment',
+      title: 'ML-Agents Reinforcement Learning Demo',
+      caption: 'Capsules trained via ML-Agents to keep the ball from falling and to navigate obstacles.'
+    },
+    tracks: {
+      'roll-a-ball': {
+        name: '3D Rolling Ball (Final Form)',
+        desc: 'The final form as the project shifted from 2D to 3D. Tilt the phone to roll the ball; snowflake bricks fall, yellow bricks bounce.'
+      },
+      'zikai-ui': {
+        name: 'zikai-ui Character Controller',
+        desc: 'The most iterated line. A 2D character with health/power stats; controls evolved from mouse, QWER/ASDF keys, finally to WASD.'
+      },
+      'main': {
+        name: 'main Character Controller',
+        desc: '2D character controller; upgraded Unity 2020 -> 2021, added on-screen buttons and jump.'
+      },
+      'doby': {
+        name: 'DobyAdventure',
+        desc: '2D side-scrolling platformer: collect coins, score, health, touch joystick.'
+      }
+    },
+    versions: {
+      'zikai-0.0.0': { control: 'Left mouse: operate, Right mouse: track', note: 'Early mouse-controlled prototype' },
+      'zikai-0.0.1': { control: 'Health Q/W/E/R, Power A/S/D/F', note: 'Introduced health/power stat system' },
+      'zikai-0.0.2': { control: 'Same as 0.0.1', note: 'Build artifact renaming' },
+      'zikai-0.0.3': { control: 'WASD move, J jump, K fly (testing)', note: 'Switched to WASD, latest of this line' },
+      'main-0.0.0': { control: 'Character controller', note: 'Baseline' },
+      'main-0.0.1': { control: 'WASD move, K jump', note: 'Upgraded Unity, added on-screen buttons' },
+      'hongXiang-0.0.0': { control: 'A/D move, jump, collect coins', note: '2D platformer' },
+      'ball': { control: 'Tilt phone to move, tilt up/tap to jump', note: 'Final version, project shifted to 3D rolling ball' }
+    },
+    screenshots: {
+      caption: 'Screenshot {n}'
+    }
   }
 }