HEL-342: 全站切换霜曜日间与黑金夜间主题

按定稿把运行时 token 换成霜曜/黑金双主题，登录与壳层接入官方 Logo 与主题记忆，不改业务接口与金额计算。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

DESIGN-TOKENS.md

@@ -1,6 +1,8 @@
 # Design Tokens
 
-This file maps the shipped dark visual system to its implementation source in `web/styles.css`. `DESIGN.md` is the portable design contract; the `:root` custom properties in `web/styles.css` are the runtime source of truth.
+**HEL-342 定稿：** 运行时视觉来源是 `web/design-system.css` 的霜曜日间 + 黑金夜间变量（`.v-fusion` / `[data-theme="night"]`），依据 `jinniu-fusion-design`。禁止退回旧青绿 token 或叠第二套覆盖层。主题偏好只存 `localStorage.jinniu-theme`（`day` | `night`），不跟随系统、不恢复业务数据。
+
+下文是历史暗色合同存档，不再作为施工依据。
 
 ## Architecture
 
@@ -8,7 +10,6 @@ This file maps the shipped dark visual system to its implementation source in `w
 - Keep shared primitives in `:root`; keep component behavior in its existing semantic rule group.
 - Business-component rules must not use `!important`.
 - Only accessibility utilities (`.sr-only`, `[hidden]`) and `prefers-reduced-motion` enforcement may force priority.
-- Do not restore warm-paper, white-card, cobalt-action, cream, or light-theme aliases. New code must consume the dark semantic tokens directly.
 - Keep administrator and cashier portals as independent route-level surfaces even when they share tokens and component primitives.
 
 ## Typography