feat(chart): add links to data point tooltips - #1438

Summary

Closes #945.

Adds an optional row-level link parameter to the chart component. When a chart data row has a link, the chart tooltip includes an accessible Open link anchor pointing to that URL.

Implementation

• Carries link through the chart template's point data without changing the existing color/z positions.
• Preserves links on aligned series points.
• Uses a small DOM-based tooltip renderer only for charts that contain links; charts without links keep ApexCharts' existing tooltip behavior.
• Handles range bars and other point-based charts, including pie-series data stored by ApexCharts as scalar values.
• Documents the parameter and adds a timeline example.

Tests

• npm test
• cargo test
• cd tests/end-to-end && npm run test -- --grep "data point link"