nopy: add create-cube command scaffolding a cube from bundled templates

Gathers id, name and directory from flags or prompts (only what the flags
do not supply), then writes manifest.mjs + deploy.py from templates under
src/templates/cube. Templates are named *.example.* so the template
directory itself can never match the loader's manifest+deploy pair rule.

The scaffold refuses a directory that already holds cube files by the
loader's own patterns, checks the id against the loaded cube set (best
effort, exempting the target directory so --force re-scaffolds work), and
warns when the target lands outside every configured cube directory.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ApuW1MMGK2pUQ9mTVRTxc5

packages/nopy/package.json

@@ -43,7 +43,7 @@
   },
   "scripts": {
     "clean": "rm -rf dist .tsbuildinfo",
-    "build": "tsc && cp src/cubes/*.mjs dist/cubes/ && mkdir -p dist/templates && cp src/templates/*.md dist/templates/",
+    "build": "tsc && cp src/cubes/*.mjs dist/cubes/ && mkdir -p dist/templates && cp -R src/templates/. dist/templates/",
     "prepack": "pnpm run build",
     "link:local": "pnpm run build && npm link",
     "nopy": "tsx src/nopy.cli.ts",