feat(bokeh): implement pie-basic

[claude]

Summary

Implements pie-basic for bokeh library.

Parent Issue: #142
Sub-Issue: #146
Base Branch: plot/pie-basic
Attempt: 1/3

Implementation

• plots/bokeh/custom/pie-basic/default.py

Details

Bokeh does not have a native pie chart method, so this implementation uses wedge glyphs to construct the pie chart manually. The implementation:

• Uses wedge glyphs to draw pie slices with proper angles
• Includes percentage labels positioned inside slices (for slices >= 5%)
• Provides interactive tooltips showing category, value, and percentage
• Supports customizable colors (defaults to PyPlots style palette)
• Includes a configurable legend
• Validates input data (empty data, missing columns, non-negative values)
• Follows PyPlots.ai style guide (colors, dimensions, typography)
• Falls back to HTML export when selenium is not available for PNG export

[github-actions]

✅ Plot Tests Passed

Created with Python 3.14

Compatibility: