Repository navigation

docs: Add a scary banner. #188

Job	Run time
test (core-markdown, test:integration)	1m 4s
test (pages-svelte-solid, test:pages:svelte-solid, 2)	47s
test (metaframeworks, test:metaframeworks, 2)	52s
test (unit, test:unit)	25s
test (pages-react-vue, test:pages:react-vue, 2)	55s
lint-and-check	32s
	4m 35s