The framework bridges in the `@supabase/server` reference import
`@supabase/middleware` directly, but the guide never said to install it.
`@supabase/server` depends on it, so npm and yarn users get it through
hoisting, while pnpm users hit "Cannot find module
'@supabase/middleware'" the moment they copy a bridge. This PR adds the
direct-dependency note to the Versions admonition, an `npm install
@supabase/middleware` line to the copy-the-bridge step, and the same
instruction to the agent migration prompt.
Katerina Skroumpelou
0f453c89fa