v0.5.0: HA notebook selector, speed-dial web, npx connect

Added

• Home Assistant notebook selector: the read endpoints accept ?notebook=<id|main>, so a read-only
  token can pull a specific owned notebook's data without switching the account's current notebook.
  A Home Assistant dashboard can now offer a notebook picker. Reads only; unknown or foreign ids fall
  back safely to the account's own current space.
• Speed dial in the web sidebar: a pad-holder's 0-9 pad now appears at the top of the wide-screen left
  hint bar, and each row sends "dial N". A bare "0" is the reserved "show my pad" key.

Changed

• Zero-checkout CLI connect: the connect line handed back with a token is now
  npx github:NTBooks/Fanad <server> <token>, so the CLI client runs from a fresh terminal (Node 24+)
  with nothing pre-installed. npx fetches, caches, and builds it on first run.
• A full-account pad-holder now sees their speed-dial pad alongside their normal first reply, rather
  than the pad replacing that first message.

Fixed

• A locked-down (speed-dial-only) account is now denied vouch in the central access gate, so it
  cannot grow the whitelist beyond its own lockdown.