feat(highcharts): implement bar-permutation-importance (#3040)

## Implementation: `bar-permutation-importance` - highcharts

Implements the **highcharts** version of `bar-permutation-importance`.

**File:**
`plots/bar-permutation-importance/implementations/highcharts.py`

**Parent Issue:** #2998

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/pyplots/actions/runs/20617503171)*

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: github-actions[bot]

plots/bar-permutation-importance/metadata/highcharts.yaml

@@ -0,0 +1,19 @@
+# Per-library metadata for highcharts implementation of bar-permutation-importance
+# Auto-generated by impl-generate.yml
+
+library: highcharts
+specification_id: bar-permutation-importance
+created: '2025-12-31T10:59:42Z'
+updated: '2025-12-31T10:59:42Z'
+generated_by: claude-opus-4-5-20251101
+workflow_run: 20617503171
+issue: 2998
+python_version: 3.13.11
+library_version: unknown
+preview_url: https://storage.googleapis.com/pyplots-images/plots/bar-permutation-importance/highcharts/plot.png
+preview_thumb: https://storage.googleapis.com/pyplots-images/plots/bar-permutation-importance/highcharts/plot_thumb.png
+preview_html: https://storage.googleapis.com/pyplots-images/plots/bar-permutation-importance/highcharts/plot.html
+quality_score: null
+review:
+  strengths: []
+  weaknesses: []