i18n: Simplified Chinese reasoning-effort labels collapse two levels

Question

## Translation issue

The Simplified Chinese labels for the reasoning-effort picker do not preserve the six distinct English levels.

English order:

`Light` -> `Medium` -> `High` -> `Extra High` -> `Max` -> `Ultra`

Current Simplified Chinese labels visibly read:

`轻度` -> `中` -> `高` -> `极高` -> `最高` -> `极高`

That makes `Extra High` and `Ultra` both appear as `极高`, so the last level looks like a duplicate and the ordering becomes unclear.

Please choose distinct Chinese terminology for all six le