feat(design): add the Macaron (07) art direction and land the Signpost (06) package files

- 07 macaron, referenced from Meowdoku: cream worlds, a white tray with
  gutters, candy tokens with white arrows, two-column 关卡/待解 HUD, white
  elevated tool discs (macaron-only exception to the flat rule), full-screen
  dark result overlay, a brick ripple on board clear, an eased glide-out and
  dot-lattice dissolve on exit; Resource Han Rounded subset fonts (SIL OFL)
  in assets/fonts with the charset and regeneration note
- 06 signpost: the design.md, tokens and preview directory that earlier
  commits left untracked
- design docs, catalog, manifest, showcase and base spec updated to seven
  directions; the analysis and proposal live in docs/art-proposal-macaron.html
- the renderer, app, geometry and CSS sources for both directions were
  already carried by the level commits made from this working tree

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -29,7 +29,7 @@ npm run dev
 - [千关审核页](http://localhost:4173/labs/campaign-review/index.html)：按章看布局，检查制作证据，逐步回放和导出本章总览。
 - [花形轨道测试](http://localhost:4173/labs/flower/index.html)：双层十二瓣与三重环带编织成花，包含 10 枚棋子的独立可玩实验，详见 [设计说明](docs/flower-study.md)。
 - [交互设计规范](http://localhost:4173/Design.html)：色板、图标、组件状态与动效示例。
-- [设计方案总览](http://localhost:4173/design/index.html)：01–05 五套设计、25 种主题、完整设计稿与多选审核入口；最新为「轻线纸境」。[方案目录](design/README.md)记录各套特点与共用规则。
+- [设计方案总览](http://localhost:4173/design/index.html)：01–07 七套设计、35 种主题、完整设计稿与多选审核入口；最新为「马卡龙」（参考 Meowdoku），主游戏用 `?design=macaron` 查看。[方案目录](design/README.md)记录各套特点与共用规则。
 - 修改端口：`PORT=4174 npm run dev`。
 
 ## 游戏规则