feat(templates): add the collapsible table page template - #6065

Adds table-collapsible, a new page template. Purely additive — table-grouped is untouched.

Why a second table-with-sections template

The two are the same silhouette solving opposite problems, and the split is the point:

useTableGroupedRows is right when every group is the same kind of thing and grouping is just a sort you can collapse — issues by status, orders by month. It is the wrong tool the moment the groups stop agreeing on what the columns mean. Utilization is a credit-card idea, pending payout is a processor idea, cost basis is an investment idea. Forcing all three into one grid produces a table that is mostly em-dashes, under a header row true of no row beneath it.

So each group owns a table, and the Card supplies the boundary the shared header row used to.

The template header comment carries the rule for extending it: the test for splitting is column divergence, not group count. Twelve groups with identical columns still belong in one table with the plugin.

What it demonstrates

• Divergent columns per group — the reason the layout exists
• One shared range (1W/1M/3M/YTD/1Y) in the page header driving all four tables
• Independent sorting per table
• Row expansion into a full-width history chart, cursor-synced across charts in the same group via Recharts syncId
• Compact layout below 720px — folds to name plus headline figure with a coloured delta, with liability inversion so a rising credit-card balance reads red

Screenshots

Blocked on core

Do not merge before these land — the template calls three props that do not exist on main yet:

• feat(Table): make row expansion behave like its sibling plugins #5995 — hasRowClickExpansion, panelVariant, divider-below-panel, and the expansion animation on useTableRowExpansion
• feat(Collapsible): let the chevron lead the trigger #5993 — chevronPlacement on Collapsible

Rubric

85/100 (B). Full marks on structure, tokens, a11y and responsive behaviour. The two deductions:

• Custom CSS (0/15) — driven by the icon-to-chevron hover cross-fade on the group headers. Worth noting the rubric is ambiguous here: scoring by CSS properties and by style keys give materially different numbers for the same file. Flagging rather than tuning the template to a metric I cannot read unambiguously.
• Naming — table-collapsible and table-grouped are both collapsible, so the name does not separate them on its own. Chosen deliberately with that tradeoff understood; the description carries the differentiation instead, which is the field that actually drives retrieval.

Test plan

• pnpm -F @astryxdesign/cli typecheck:strict — clean
• pnpm -F @astryxdesign/cli typecheck:template-docs — clean
• Preview verified at four viewports, zero console errors in all four
• table-grouped byte-identical to main