Control-surface parity — the three display axes

One user-facing word per axis, identical across CLI · env · SPA · Mac app. "theme" is banished from every user surface (it means research findings — the Themes tab); internal data-color-theme/color_scheme stay as-is. CLI & env are English-only; the SPA & Mac columns re-render in the locale you pick.
Locale

⚠ Why "palette" and never "theme" — the CJK collision

In Latin-script locales, appearance / palette / theme are three unrelated everyday words, so there's no clash. But in Japanese, Korean, and (proposed) Traditional Chinese, the software word for a colour "theme" is the same loanword already shipped for research findings — so a "colour theme" picker would read identically to the Themes report tab. The escape is the "palette" word:

ja — research テーマ  =  software "theme" テーマ  →  palette must be カラーパレット (or 配色)
ko — research 테마  =  software "theme" 테마  →  palette must be 색상 팔레트
zh-Hant — research 主題  =  software "theme" 主題  →  palette must be 調色盤 (or 配色). Never 主題 / 佈景主題.
Legend verified in the shipped locale files Proposed by i18n review (new "palette" keys + Default/Edo) Indicative option values — gate CJK on native reviewers