feat: require caller-owned Redis clients

[lan17]

Summary

This PR makes Redis connection ownership explicit and removes DialCache's lazy client factory.

Applications now create and connect a Redis client, adapt it to DialCacheRedisClient, and pass it through redis.client. DialCache borrows that client for cache operations but never creates, connects, drains, disposes, or closes it.

Ownership contract

• The application owns the underlying Redis/Valkey client lifecycle.
• During shutdown, the application stops new DialCache-backed work and awaits all cached-function and invalidateRemote() promises, including fallbacks that may still enqueue a Redis write.
• The node-redis adapter owns no resources; the application closes node-redis after draining.
• The GLIDE adapter owns its five Script handles only; the application disposes the adapter after draining, then closes the GLIDE client.
• DialCache deliberately does not gain a close() or lifecycle subsystem.

Public API and migration

• RedisConfig.client is now required.
• RedisConfig.createClient is removed.
• The root-exported RedisClientFactory type is removed.
• Untyped callers using the legacy createClient property receive an explicit migration error.

Migration is straightforward: move the old factory body into application startup, retain the client handle, and pass the connected adapter as redis.client. Direct clients already worked in previous releases, so applications can deploy the migrated construction before upgrading DialCache.

This does not change cache keys, Redis frames, Lua protocols, metrics, hit/miss semantics, or fail-open behavior, so rolling upgrades and rollbacks remain wire-compatible.

Runtime impact

Redis operations now use the semantic client directly. This removes the retained factory promise and per-operation client resolution while leaving read, write, invalidation, and fallback behavior unchanged.

Validation

• Node 22 full pnpm check: 179 tests, typecheck, coverage, build, declarations, and packed-package smoke
• Node 22 real-Redis integration suite: 46 tests
• Node 22 focused Redis/adapter suite: 31 tests
• Node 20.17 packed ESM/CJS/type consumer test
• git diff --check
• Two independent final reviewers returned no findings

Resolves #20