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>

assets/fonts/README.md

@@ -0,0 +1,13 @@
+# 资源圆体子集（Resource Han Rounded）
+
+来源：[CyanoHao/Resource-Han-Rounded](https://github.com/CyanoHao/Resource-Han-Rounded) v0.990，CN 版 Medium 与 Bold，SIL Open Font License 1.1。用户于 2026-09-14 指定，用于第 07 套「马卡龙」的界面文字。
+
+`ResourceHanRoundedCN-Medium.subset.woff2` / `ResourceHanRoundedCN-Bold.subset.woff2` 是按 `macaron-charset.txt` 裁剪的子集（游戏界面、弹窗与 v0.1–v0.5 关卡数据中出现的 1001 个字符，含 ASCII 与常用标点），每个约 170 KB。子集里没有的字符由浏览器按字形回落到 PingFang 等系统字体。
+
+重新生成（fonttools + brotli）：
+
+```sh
+pyftsubset ResourceHanRoundedCN-Medium.ttf --text-file=macaron-charset.txt --flavor=woff2 --layout-features='*' --no-hinting --desubroutinize --output-file=ResourceHanRoundedCN-Medium.subset.woff2
+```
+
+新增大量界面文字或关卡文案后，把新字符加入 `macaron-charset.txt` 再重新裁剪。原生端可直接使用完整 TTF。