feat: Add Store.redis() for standard Redis/ioredis/Valkey clients

[tenequm]

Problem

Store.upstash() works because the Upstash REST SDK auto-serializes JSON (including BigInt) on their end. Standard Redis clients (ioredis, node-redis, Valkey) only accept strings, so passing channel state with BigInt fields directly to client.set() either throws or corrupts data.

Anyone running self-hosted Redis/Valkey (common in Kubernetes deployments) has to write a custom store adapter with BigInt-safe serialization:

const BIGINT_SUFFIX = "#__bigint";

function createRedisStore(redis: IoRedis): Store {
  return Store.from({
    async get(key) {
      const raw = await redis.get(key);
      if (raw == null) return null;
      return JSON.parse(raw, (_, v) =>
        typeof v === "string" && v.endsWith(BIGINT_SUFFIX)
          ? BigInt(v.slice(0, -BIGINT_SUFFIX.length))
          : v,
      );
    },
    async put(key, value) {
      await redis.set(
        key,
        JSON.stringify(value, (_, v) =>
          typeof v === "bigint" ? \`\${v}\${BIGINT_SUFFIX}\` : v,
        ),
      );
    },
    async delete(key) {
      await redis.del(key);
    },
  });
}

This is error-prone and every self-hosted user will rediscover the BigInt serialization issue independently.

Proposal

Add Store.redis() that accepts any client with standard get/set/del string methods and handles #__bigint serialization internally (using ox's Json.parse/Json.stringify, same as Store.cloudflare() and Store.memory() already do):

import { Store } from "mppx/server";
import Redis from "ioredis";

const redis = new Redis("redis://localhost:6379");
const store = Store.redis(redis);

// Works with any client that has get/set/del string methods:
// - ioredis
// - node-redis (@redis/client)
// - Valkey

Why not extend Store.upstash()?

• upstash is named after a specific product - using it for generic Redis would be confusing
• The serialization behavior is fundamentally different (Upstash auto-serializes, standard clients don't)
• A separate Store.redis() is additive with no breaking changes

Interface

export function redis(client: redis.Parameters): Store

export declare namespace redis {
  type Parameters = {
    get: (key: string) => Promise<string | null>
    set: (key: string, value: string) => Promise<unknown>
    del: (key: string) => Promise<unknown>
  }
}

This covers ioredis, node-redis, and any Redis-compatible client without requiring a specific package dependency.

[jxom]

PR welcome!

[tenequm]

@jxom here it is, just wanted to verify and test everything in my own setup before publishing a solution:
#210