Challenge 3: Trace the Site's Three Mentions — Possible Solution
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1. node3-5 (Node.js Advanced, Caching Strategies) — briefly mentioned
   "Redis patterns" as an example of in-memory caching approaches,
   without teaching Redis itself. This course's CHAPTER 5 (Expiration
   & Caching Patterns) goes deep on this: TTL/EXPIRE, the cache-aside
   pattern, and cache stampede prevention.

2. node3-6 (Node.js Advanced, Message Queues) — briefly mentioned
   "Redis Streams" as one queue-like option, again without teaching it
   directly. This course's CHAPTER 7 (Redis as a Queue: Lists vs
   Streams) goes deep on this: simple list-based queues, Redis
   Streams specifically, and consumer groups.

3. web-sockets1-7 (WebSockets & Real-Time Communication, Scaling
   WebSockets) — briefly mentioned a "Redis pub/sub adapter" as the
   mechanism for scaling WebSocket rooms across multiple servers.
   This course's CHAPTER 6 (Pub/Sub & Scaling Real-Time Apps) goes
   deep on this: PUBLISH/SUBSCRIBE from first principles, building up
   to exactly the scaling pattern that chapter only gestured at.

All three followed the same shape: an existing course used Redis as a
named example without ever teaching the tool itself, which is exactly
the gap this course exists to close.