Switch examples from Redis Stack to Redis 8

Summary

Several user-facing examples in this repo still use Redis Stack images. Those examples should be updated to use Redis 8 (redis:8) instead.

Redis 8 includes the formerly separate modules needed by this project, so the docs/examples should reflect the current default recommendation and avoid steering users toward older Redis Stack images.

Places to update

• docs/quick-start.md
  • docker run -d --name redis-stack -p 6379:6379 redis/redis-stack:latest
• docker-compose.yml
  • image: redis/redis-stack-server:${REDIS_VERSION:-latest}
• docker-compose-task-workers.yml
  • image: redis/redis-stack-server:${REDIS_VERSION:-latest}

Expected outcome

• All example commands and compose snippets use redis:8
• Wording refers to Redis 8 rather than Redis Stack
• Quick-start guidance stays aligned with the repo's current Redis recommendation

Notes

I also noticed .github/workflows/python-tests.yml still includes a Redis Stack image in the test matrix. That may be intentional for compatibility coverage, so it could be handled separately if needed.

Start with docs/quick-start.md, docker-compose.yml, and docker-compose-task-workers.yml, then inspect the existing Redis image and wording in each location. Update the listed examples to Redis 8 and ensure the commands and compose snippets consistently use redis:8; leave the separately noted test matrix for separate consideration.