[SCIEDU-111] Implement the Experimenter Admin Dashboard

[rickLHY]

Summary

• implement the experimenter admin dashboard
• align admin data access with the SciEdu API specification
• add responsive layouts and local demo mode for preview

API integration

• GET /api/users/me
• GET /api/users
• GET /api/experiments
• GET /api/experiments/{id}
• GET/POST /api/experiments/{id}/participants
• GET /api/experiments/{id}/courses

Supersedes #47, which GitHub automatically closed when its source branch was renamed.

[chatgpt-codex-connector]

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[AshanEason]

下方這個 Footer 高度固定沒錯，不過下面不避留白 感覺可以透過設定 table scroll 有 min height，或是讓 Footer 留在 Card 的最底下。

[AshanEason]

你做得超棒辛苦了！我覺得誠品跟設計圖非常吻合，剩下你再照我留的 comment 改就好，有問題再找我！