Overall improvements including users list, and added robots.txt

src/app.html

src/hooks.server.ts

src/lib/components/Header.svelte

src/lib/components/inputs/SelectField.svelte

src/lib/components/inputs/TextField.svelte

src/routes/(admin)/users/+page.svelte

src/routes/(user)/playlists/+page.svelte

static/robots.txt