Fixes an issue where running the sandbox (code component) fails due to
unresolved hostnames. Added missing service names (es01, infinity,
mysql, minio, redis) to 127.0.0.1 in the /etc/hosts example.
Reference: https://github.com/infiniflow/ragflow/issues/8226
## What this PR does
Updates the sandbox quickstart documentation to fix a known issue where
the sandbox fails to resolve required service hostnames.
## Why
Following the original instruction leads to a `Failed to resolve 'none'`
error, as discussed in issue #8226. Adding the missing service names to
`127.0.0.1` resolves the problem.
## Related issue
https://github.com/infiniflow/ragflow/issues/8226
## Note
It might be better to add `127.0.0.1 es01 infinity mysql minio redis` to
docs/quickstart.mdx, but since no issues appeared at the time without
adding this line—and the problem occurred while working with the code
component—I added it here.
### Type of change
- [X] Documentation Update
