Update docs Reference page(s)

Page: https://docs.nhost.io/reference Source: docs/src/content/docs/reference/index.mdx

Problem

The Reference landing page does not reflect what is actually in the Reference section. The sidebar has seven top-level groups; the landing page accounts for four of them, and one of those is an empty section.

What the page currently has:

Section on page	State
Backend Services	Describes Auth and Storage in prose but links to neither
Client Libraries	Links @nhost/nhost-js
Templating	Links Kriti
Deprecated Libraries	Heading and one sentence, no links at all

What is in the sidebar but missing from the page entirely:

• Configuration — /reference/configuration
• GraphQL — /reference/graphql
• CLI — /reference/cli

Proposed changes

• Add direct links to /reference/auth and /reference/storage under Backend Services instead of only describing them
• Add a Configuration section linking /reference/configuration
• Add GraphQL linking /reference/graphql
• Add CLI linking /reference/cli
• Either populate Deprecated Libraries with the actual deprecated packages or drop the heading

Why it matters

This page is the entry point to the whole Reference section, for humans and for the machine-readable docs work (llms.txt / llms-full.txt). Anything not linked from here is effectively undiscoverable unless you already know it exists in the sidebar.

Acceptance criteria

Every top-level group in the Reference sidebar is represented and linked from /reference, and there are no headings without content.