[max-models]

The interactive figures of the guides are now web figures shown by the docs theme's PlotlyFigure (starlight-theme 0.8). The site's own PlotlyChart is removed.

• The figure scripts (generate_docs_figures.py, generate_gvec_figures.py, generate_desc_figures.py) write public/plotly/<name>.plotly.json through PlotResult.save (Save plots as web figures for the docs theme #97). The two figures made directly in Plotly (the hand-built slice and the profile Gantt chart) go through PlotResult(fig).save too.
• All 28 <PlotlyChart src=… height=…> in the guides become <PlotlyFigure src="….plotly.json">. The page reserves each figure's space from its aspect ratio, so the fixed heights are gone.
• plotly.js now comes from the theme (npm, loaded when a figure scrolls into view) instead of a CDN script. Converted Matplotlib figures keep their white plot area (white_plot), as PlotlyChart did. The other colours follow the theme.
• The Plotly guide has a short section on embedding a .plotly.json in an MDX page.

Checks:

• I ran generate_docs_figures.py locally: all 21 of its figures are written, with an aspect hint, and the animations keep their frames. The GVEC and DESC figures need those packages and are generated in CI.
• In the dev server, the Plotly guide's four figures render in light and dark mode. The dev server needs PlotlyFigure: plotly.js unbundled in dev, plot inside the frame starlight-theme#56 to load plotly.js, and a production build is not affected.
• The pre-commit hooks pass.