v0.2.1: correct the access-token path

Fixed

• Setup instructions pointed at a token path that dead-ends as written. The Canvas
  control lives under 帳戶 → 設定 → 已核准的整合 → 新訪問令牌, and NTU COOL's
  custom theme hides that entire block:

  .approved_integration_headers, .approved_integration_content { display: none; }

  So a reader following the documented path looks for a button inside a section
  they cannot see, and concludes the feature is unavailable.

  Corrected in all four places that carried the old path: the README setup step,
  the server's own instructions string (delivered to the client — the model was
  reading the wrong path too, and would have relayed it), the ntucool-canvas
  skill, and the wrapper's token-missing stderr hint.

  The hide is cosmetic, not Canvas's limit_personal_access_tokens account
  setting — .add_access_token_link is still rendered into the page, so tokens
  remain obtainable. Verified against a live NTU COOL session 2026-08-19.