feat(data_table): DataTable component with TanStack Table Core

[djalmaaraujo]

Summary

Adds a fully-featured DataTable component powered by TanStack Table Core (framework-agnostic, vanilla JS) and wired with a Stimulus controller.

Architecture: TanStack manages all table state (pagination, sorting, filtering, row selection, column visibility, row expansion) client-side. For server-driven tables, the Stimulus controller fetches JSON from a src: endpoint and re-renders rows via JS. For static tables, everything works entirely client-side with no server round-trips.

Components added

• DataTable — root wrapper, hosts the Stimulus controller
• DataTableContent — renders <table>, <thead>, <tbody> with Stimulus targets; includes <template> elements for sort icons, checkboxes, chevrons, and expanded row markup
• DataTableToolbar — search input + per-page selector
• DataTableBulkActions — selection count bar with slot for action buttons
• DataTableColumnToggle — column visibility dropdown (show/hide columns)
• DataTablePagination — prev/next buttons + page indicator
• DataTableCell* — typed cell renderers: Text, Badge, Currency, Number, Percent, Date, Boolean, Link, Truncate
• DataTableExpandedRow — content slot for expandable rows

Stimulus controller features

• Server-driven mode (src: value) — fetches application/json, updates TanStack data, re-renders rows
• Client-side mode (no src:) — sort, filter, paginate entirely in-browser
• URL sync (sync_url: true) — reflects current page/sort/search in the address bar
• Row selection with bulk actions, select-all checkbox
• Column visibility toggle with server-aware refetch
• Expandable rows
• Generic TanStack options pass-through (options: value) for advanced use cases

Docs page

Full interactive demo with 100 fake employees, server-side search/sort/pagination via a demo controller (Docs::DataTableDemoController). Includes prose documentation, code examples for all major features, and a component API table.

Test plan

• Visit /docs/data_table — hero demo loads with 10 rows
• Search filters rows; URL updates
• Click a column header to sort asc/desc; URL updates
• Navigate pages; URL updates
• Change per-page selector
• Select rows; bulk actions bar appears with correct count
• Toggle column visibility — columns show/hide
• Expandable rows example works
• Client-side sort example (no src:) works without network requests