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>

design/manifest.json

@@ -9,7 +9,7 @@
   "catalog": "design/index.html",
   "example": "design/examples/render-design.mjs",
   "defaultDesignId": "calm",
-  "latestDesignId": "paper",
+  "latestDesignId": "macaron",
   "selectionPolicy": "multiple-candidates",
   "themeIds": [
     "lagoon",
@@ -92,6 +92,30 @@
       "tokens": "design/directions/paper/tokens.json",
       "preview": "design/directions/paper/index.html",
       "legacyPreview": "design/directions/paper.html"
+    },
+    {
+      "id": "signpost",
+      "code": "06",
+      "name": "路标",
+      "artStyle": "signpost",
+      "status": "review-candidate",
+      "directory": "design/directions/signpost",
+      "designDoc": "design/directions/signpost/design.md",
+      "tokens": "design/directions/signpost/tokens.json",
+      "preview": "design/directions/signpost/index.html",
+      "legacyPreview": "design/directions/signpost.html"
+    },
+    {
+      "id": "macaron",
+      "code": "07",
+      "name": "马卡龙",
+      "artStyle": "macaron",
+      "status": "review-candidate",
+      "directory": "design/directions/macaron",
+      "designDoc": "design/directions/macaron/design.md",
+      "tokens": "design/directions/macaron/tokens.json",
+      "preview": "design/directions/macaron/index.html",
+      "legacyPreview": "design/directions/macaron.html"
     }
   ]
 }