Restructure into pnpm monorepo with game shell, docs, and SpacetimeDB backend

- Restructure flat static prototype into pnpm workspace monorepo
- apps/game: playable shell with R3F 3D scene, HUD, SpacetimeDB connection
- apps/docs: design docs and prototypes
- apps/site: landing page
- packages/ui: shared Button and Panel primitives
- services/spacetimedb: backend module (9 tables, 11 reducers)
- Archive legacy static files to archive/legacy-static/
- Game loop: connect, undock, target, approach, dock, mine, sell
- Add pnpm-workspace.yaml, tsconfig.base.json, spacetime.json

archive/legacy-static/gdd-docs-hub.html.artifact.json

@@ -0,0 +1,21 @@
+{
+  "version": 1,
+  "kind": "html",
+  "title": "GDD::DOCS — Game Design Documentation Hub",
+  "entry": "gdd-docs-hub.html",
+  "renderer": "html",
+  "status": "complete",
+  "exports": [
+    "html",
+    "pdf",
+    "zip"
+  ],
+  "createdAt": "2026-05-22T01:27:51.600Z",
+  "updatedAt": "2026-05-22T01:27:51.696Z",
+  "sourceSkillId": "blog-post",
+  "metadata": {
+    "identifier": "gdd-docs-hub",
+    "artifactType": "text/html",
+    "inferred": false
+  }
+}