Add interactive BasinPie charts

[krowvin]

Summary

• add a reusable, accessible RadialFillChart SVG component
• add the CWMS-aware BasinPie adapter for preloaded level/time-series data or optional CDA loading by levelIds and tsids
• document both data modes with working examples
• fit and position chart labels, titles, percentage guides, and captions to avoid clipping and collisions

Why

The SWT sites maintained separate D3 BasinPie renderers, including expression-based label positioning. Moving the interactive renderer into Groundwork Water provides one declarative React/SVG implementation while keeping application navigation and project configuration in the consumers.

Impact

Consumers can provide loaded CWMS data or identifiers plus an office. The chart handles loading, error, empty, missing-data, mouse, and keyboard states and remains compatible with static SVG markup.

Validation

• npm test - 44 tests passed
• npm run build-lib
• npm run build-docs
• public SWT production build against the linked package
• internal SWT cwbi-local build against the linked package

[krowvin]

Documentation screenshot

BasinPie with application-provided data — This is the deterministic levelData/tsData example from the Groundwork Water docs. It shows weighted storage segments, 25/50/75/100% guide rings, the aggregate 53% title, CHAR's missing-storage warning, project percentages, and the image-date caption.

[msweier]

This looks good! I tested in docs. I didn't think I would need it but I thought of a couple places with reservoirs in series where I could.