v0.39.0 — Redis integration

A Redis integration on a pluggable RedisConnection driver — the core imports no client, so it runs on Node and the edge.

• setRedis(driver) then redis(): get / set (with { ex } / { px } TTL) / del / exists / incr / decr / incrBy / expire / ttl / keys / flushAll, plus getJson / setJson and a remember read-through cache.
• MemoryRedis — a full in-memory, TTL-aware driver and the default, so redis() works in tests with no setup. Point it at Upstash (fetch), ioredis, or node-redis in production (Upstash adapter example in the docs).
• redisStore() adapts the client into a CacheStore, so the cache can be Redis-backed (shared across instances).

234 tests; type-checked doc examples. See docs/redis.md.