Replace the stale, disclaimer-topped API reference with one that matches the
cache/API library on `next`, and fix the Getting Started library snippet and
CLI-surface prose that the library rewrite left wrong. Documents `Library.open`
and its options (XDG cache default, refresh interval, precache, cache bounds,
pools), the default-read vs `fresh()` distinction and that the CLI's read
commands are fresh, the record types with `snapshot()`/`subscribe()`, the
`albums`/`photos`/`timeline` read surface, `Photo` content methods,
`thumbnails.ensure`, the `mldata` search surface, `backup()`, the three request
pools (10/5/25), and the on-disk cache layout. Notes the deferred content-hash
integrity check (issue #68). Also this is issue #13.
Docs-only: no code changed. Every documented signature was verified against the
source on `next`.
Model: opus-4-8
sneak