Add curated chart/infographic reconstruction case

[swernerx]

Goal

Add a curated case for charts or infographic-style graphics, such as a small bar chart, line chart, or annotated metric card.

Why this matters

Charts are a practical raster-to-SVG use case: people often want to recover a clean, editable version of a chart from a screenshot or exported bitmap. The hard part is not only tracing shapes. The output should preserve axes, bars or lines, markers, legends, and repeated visual styles.

Example case requirements

• Include axes or grid lines, repeated bars/markers/points, labels or text-like regions, and a legend or annotation.
• Use at least three colors with clear semantic roles.
• Avoid requiring OCR as a first milestone; text can be bounded and deferred.
• Prefer a bitmap with antialiased lines and small UI-like details.

Acceptance criteria

• Add a curated suite entry with a family such as chart_infographic.
• Define expected contracts for axis strokes, bars/markers, legend swatches, and text-like regions.
• Reports should expose whether repeated chart elements were preserved as coherent groups.
• Add tests for any chart-specific grouping or repeated-marker behavior.
• Existing curated cases and primitive quality gates remain green.

Notes

A good first target is a simple 4-6 bar chart with a legend. Line charts and dense dashboards can follow after the first chart case is stable.