Redirect/pool: endpoint matching has no normalization, newest hint not preferred, cache TTL/entries not configurable, TableSessionPool lacks acquire_for_device

Smaller redirect/pool issues around `acquire_for_device`:

1. **Redirect endpoint matching is exact host-string equality with no normalization**. Hostname-vs-IP spelling silently disables the optimization on multi-DataNode clusters, with no log line so it is invisible from outside. At minimum the comparison should normalize case/whitespace and resolve hostname-vs-IP where feasible.
2. **When idle sessions hold conflicting hints for one device, the winner is queue position, not recency.** `RedirectCache` already tracks `seq`/insertion order — prefer the newest hint (this stays within the documented "any idle session" behaviour).
3. **`RedirectCache` TTL and `max_entries` are fixed at construction** with no `SessionConfig` knob; this becomes measurable on large batch inserts. Add `SessionConfig` fields with the current defaults.
4. **`TableSessionPool` exposes `acquire()` but not `acquire_for_device()`**, so table-mode users accumulate hints no pool API can consume. Expose the underlying `SessionPool::acquire_for_device`.

Commencez par localiser RedirectCache, SessionConfig, TableSessionPool et SessionPool::acquire_for_device, puis suivez la manière dont acquire_for_device sélectionne les sessions inactives et dont les indications de redirection sont comparées. Vérifiez les tests existants du pool et de redirect, et contrôlez que les quatre comportements demandés sont couverts : correspondance normalisée, sélection de l'indication la plus récente, valeurs par défaut actuelles configurables et API du pool de tables.

Rédigé par le modèle d'indexation à partir du texte de l'issue.