[upstream #16489] #16489: Make DataTable Row Estimates Breakpoint- and Leaf-Column-Aware

[berry-13]

DataTable (packages/client/src/components/DataTable.tsx) now seeds its virtualizer from the themed row geometry (useTableRowHeight('titled' | 'compact')) instead of canary's flat 48px. Rendered rows are measured through measureElement, so only the estimate for rows not yet rendered, and with it the initial scroll height, can be off. Two ways it still is:

1. Breakpoints: below sm, TableCell size="compact" renders dense padding and text-xs (about 24px), while the compact estimate is 36px. useTableRowHeight re-reads only on root style/class mutations, so crossing sm does not refresh the estimate.
2. Column shape: hasTitleColumn inspects top-level columns only. A grouped definition ({ columns: [{ accessorKey: 'title' }] }) gets the compact estimate although its leaf renders a 48px title cell, and a title column hidden through column visibility still selects the titled estimate.

Suggested fix: derive the title check from table.getVisibleLeafColumns(), and make the row-height read breakpoint-aware (subscribe to the sm media query as well as root mutations).

Raised by the local cross-family review on LibreChat-AI#16489 (local:744d1f2:L-001, L-002). Outside that change's contract (theme roles for table header, row rule and density); not a regression against canary, which used a constant estimate.

[berry-13]

Two more variants from the local review of 09452c8 on LibreChat-AI#16489, same cause (the estimate for unmounted rows refreshes only on root style/class mutations):

• local:09452c8:L-001: compact rows below sm render dense cells, so the compact estimate is too tall on mobile (duplicate of item 1 above).
• local:09452c8:L-002: a change to --theme-table-cell-space-y, --theme-table-row-stroke or the root font size that arrives through a stylesheet or media query rather than a root style/class mutation is not observed. The fix above (subscribe to the sm media query as well as root mutations) should also cover a root font-size change; a stylesheet-only source can be handled by re-reading on the theme provider's change event.

[berry-13]

One more variant (local:ed9f387:L-001 on LibreChat-AI#16489): with tableCellSpaceY: 0px the titled estimate is 1rem (the fixed header height) while the title cell's own text-sm line needs 1.25rem, so unmounted titled rows are estimated short. Estimate titled rows as the larger of the fixed header height and the compact content height.