feat: TtlSortedCache::set_with builder, ConcurrentCachePeek, ConcurrentCachedExt::try_get_or_set_with

[jaemk]

Three v3 API changes plus a macro cleanup.

• Replace the TtlSortedCache inherent setters set_with_ttl / set_evict / set_with_ttl_evict with an entry-setter builder: cache.set_with(k, v).ttl(d).evict().set(). set_with_ttl_evict took Option<Duration> while set_with_ttl took a bare Duration; the builder makes each option independent and gives one spelling per combination. Plain set(k, v) and Cached::cache_set are unchanged. TtlSortedSetBuilder is re-exported at the crate root and from cached::stores, gated on time_stores.
• Add ConcurrentCachePeek<K, V>, moving the sharded peek onto a trait so generic code over a concurrent store can read without side effects: no recency promotion, no TTL refresh, no hit/miss metrics, no lazy removal of expired entries. Implemented by the six sharded stores only (Error = Infallible); the IO stores are excluded because they cannot peek without a full read. The concrete sharded types keep their inherent peek, which retains call-site priority. Exported from the prelude.
• Add ConcurrentCachedExt::try_get_or_set_with, completing the short-alias set for ConcurrentCached::cache_try_get_or_set_with to match CachedExt.
• Remove a no-op #[allow(non_snake_case)] from the #[cached] Clone assertion expansion.

Breaking changes are covered in the changelog and both migration guides. New coverage is in tests/v3_ttl_sorted_set_with.rs and tests/v3_additive_parity.rs.