[jaemk]

• Lead the README with a memoized get_user example (max_size + ttl_secs, Err not cached), install snippet, and a table of contents.
• Replace the reference-style crate docs with short task sections: the three macros, common attributes, Result/Option returns, async, Redis and disk, using stores directly, choosing a store, per-value expiry, feature flags, requirements, upgrading.
• Move the store reference (method naming, store comparison, sharding, behavioral guarantees, inspection APIs, per-value expiry, performance notes) to the stores module docs, which had none.
• Move the full attribute reference, synchronization details, requirements, and the Redis/disk/#[concurrent_cached] examples to the macros module docs; drop crate-root examples that duplicated ones already there.
• Update test comments that pointed at the README for quoted diagnostics.

No API change. README goes from 945 to ~320 lines.