docs: add AgentsKit Redis memory recipe

[EmersonBraun]

Summary

• add a TypeScript recipe for Redis-backed AgentsKit conversation memory
• isolate sessions by conversation ID and refresh a native Redis TTL on every save
• demonstrate snapshot replacement and explicit deletion
• add credential-free unit tests and a live Redis demo
• add one plain entry at the bottom of the Agents recipes table

Why

This gives TypeScript developers a small, provider-neutral reference for persistent
agent conversations. The memory contract can be used with any model or runtime.

Validation

• npm test — 2 passed
• npm run check
• live Redis 8 demo persisted two isolated conversations
• Redis reported TTL 300 for the retained conversation
• clearing one conversation left only the other key
• git diff --check

[EmersonBraun]

Hi — would this recipe still be useful in redis-ai-resources? It remains mergeable and includes credential-free tests plus a Redis 8 run covering isolation, TTL, replacement, and deletion. I'm happy to adjust the scope or formatting.