update(raincloud-basic): pygal — fix orientation consistency (#4229)

## Summary

Updated **pygal** implementation for **raincloud-basic**.

**Changes:** Fix cloud/rain orientation so cloud (half-violin/KDE)
extends UPWARD and rain (jittered points) falls DOWNWARD from each
category line.

### Changes
- Fixed orientation: cloud now extends upward (positive y-direction),
rain falls downward
- Updated spec to use absolute directional terms instead of ambiguous
"TOP"/"BELOW"
- Preserved existing review strengths

## Test Plan

- [x] Preview images uploaded to GCS staging
- [x] Implementation file passes ruff format/check
- [x] Metadata YAML updated with current versions
- [ ] Automated review triggered

Fixes #3745

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Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: MarkusNeusinger