Charts docs: reconcile with Charts module 6.3.2

[rahmanunver]

Summary

Reconciles the Charts documentation with the current Charts module (v6.3.2, Studio Pro 10.6 and above). Builds on the earlier Charts PRs (Plotly how-to removal, configuration page updates, Any Chart deprecation).

Marketplace Guide (/appstore/widgets/charts/)

• Charts overview restructured: chart types, common properties (the tabs of the Edit Series Item dialog box, General, Dimensions, Advanced), and the customization model. Documents Show playground slot instead of the removed developer mode, and Enable advanced options, which controls whether the Advanced tab properties are visible.
• New reference page per chart type: area, bar, bubble, column, heat map, line, pie, and time series. Each lists only its type-specific properties.
• New Chart Playground reference page (/appstore/widgets/chart-playground/).
• Custom chart: full property reference (Dimensions, Events).
• Fine-tuning and theme how-tos updated for the playground-slot workflow, Enable advanced options, and Enable theme folder config loading.
• Tutorials (create, dynamic series, REST): series steps match the Studio Pro UI (New in the Series list, Edit Series Item dialog box tabs). Create a Basic Chart no longer uses a data view.
• Legacy (below 3.0.0) section trimmed to a pointer to the legacy refguide page and the mendixlabs v1.4.4 cheat sheet.
• Aliases for stale widget help URLs: /appstore/widgets/ChartPlayground/, /appstore/widgets/time-series-chart/.

Studio Pro Guide (refguide 11 and 10)

• Charts overview: intro rewritten, links to the Custom chart and Chart Playground pages, and points to the Marketplace Guide for configuration. Sample chart images refreshed.
• Chart Configuration: marked as legacy (below 3.0.0), with a description added.
• Advanced cheat sheet, Any Chart configuration, and charting with view entities: added descriptions and image alt text, and updated old /howto/ links to the current URLs.

Notes for Reviewers

• New Studio Pro 11 and runtime screenshots across the chart pages, with alt text. No {{% todo %}} markers remain.
• Property captions, values, and defaults were checked against the widget XML in mendix/web-widgets.
• hugo --environment development builds with 0 errors. Internal links, anchors, and images on all chart pages resolve.