### What problem does this PR solve?
_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._
### Type of change
- [ ] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [x] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):
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
