Ensure code generated by create-puck-app can be built

[chrisvxd]

The code generated by the generator doesn't get built on publish, which makes it easy to publish code that will fail when the user tries to build it. We should build all recipes as generated by the generator as part of a GitHub workflow for PRs, failing if any build fails.

To test generators, we need to:

• either generate a new app and compile that
• or share code between the recipes and generator, and build the recipe (see Generate templates from recipes #10)

Example: #46

[chrisvxd]

@abhishek276533 following on from #59, I can reproduce on a clean-clone. It's possible something was getting cached.

I'll investigate and report back.

yarn run v1.22.19
$ next build
- info Creating an optimized production build
- info Compiled successfully
- info Linting and checking validity of types
- info Collecting page data
[    ] - info Generating static pages (0/4)TypeError: Cannot read properties of null (reading 'root')
    at Module.generateMetadata (/Users/chrisvilla/Projects/tmp/puck/recipes/next/.next/server/chunks/801.js:175:29)
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/lib/metadata/resolve-metadata.js:199:24
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/server/lib/trace/tracer.js:117:36
    at NoopContextManager.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7057)
    at ContextAPI.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:516)
    at NoopTracer.startActiveSpan (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18086)
    at ProxyTracer.startActiveSpan (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18847)
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/server/lib/trace/tracer.js:106:107
    at NoopContextManager.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7057)
    at ContextAPI.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:516)

Error occurred prerendering page "/". Read more: https://nextjs.org/docs/messages/prerender-error
TypeError: Cannot read properties of null (reading 'root')
    at Module.generateMetadata (/Users/chrisvilla/Projects/tmp/puck/recipes/next/.next/server/chunks/801.js:175:29)
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/lib/metadata/resolve-metadata.js:199:24
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/server/lib/trace/tracer.js:117:36
    at NoopContextManager.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7057)
    at ContextAPI.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:516)
    at NoopTracer.startActiveSpan (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18086)
    at ProxyTracer.startActiveSpan (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:18847)
    at /Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/server/lib/trace/tracer.js:106:107
    at NoopContextManager.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:7057)
    at ContextAPI.with (/Users/chrisvilla/Projects/tmp/puck/recipes/next/node_modules/next/dist/compiled/@opentelemetry/api/index.js:1:516)
- info Generating static pages (4/4)

> Export encountered errors on following paths:
	/page: /
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.