Render AE drill-down listings lazily to shrink the ae_forestly() widget

The work is in the ae_forestly() function, which builds a widget. The drill-down listings are currently built as nested reactable tables. The first step is to understand the existing details function and the inst/js/search-filter.js file. The change depends on an external lt.js extension from the lt repo. Once that is available, embed AE listing data as JSON and replace the R-side details renderer with a client-side JS callback. Verify features by testing sorting, search, and filtering in the drill-down.

Background

Follow-up to #147 (running-time / output-size optimization). #157 removed the duplicated per-nested-table search/filter JS (widget ~1.4 GB → ~350 MB at 1,000 subjects). Profiling the remainder shows the drill-down listing tables are now ~70%+ of the widget: ae_forestly() builds one nested reactable per main-table row (44,865 rows in the profiled case), and each carries ~3 KB of scaffolding regardless of content. All of them are serialized eagerly into the self-contained HTML even though a user only ever expands a few.

Measured at 300 subjects: 13,673 rows, 59.9 MB total; per-row drill-down ≈ 3,135 B.

Proposal

Render the drill-down lazily on the client, and embed the listing data once:

1. Embed the AE listing data a single time as compact, column-oriented JSON (a page global keyed by parameter + AE term), instead of one pre-built table per row.
2. Replace the R-side details = function(index) { reactable(...) } with a client-side details = JS("function(rowInfo){ … }") (reactable supports a JS() details renderer). On expand, the callback slices the embedded data for that term and renders an interactive table into the expanded container.
3. Render that table with a lightweight interactive lt table (sort + search/filter + paging), via the planned lt.js interactive extension.

Expected impact

• Drill-down scaffolding (~141 MB at 1,000 subj) collapses to one shared renderer + the listing data embedded once → projected total ~340 MB → ~60–100 MB.
• The per-row R-side reactable construction disappears, so most of the ~605s ae_build stage (this box; single-core) goes away too.

Behavior to preserve

• Drill-down keeps column sorting, table-wide search, per-column filters, and paging (current reactable features).
• Search semantics unchanged: substring, ! negation, and x-expression (currently in inst/js/search-filter.js).
• Main table and crosstalk (param selector + incidence slider) are unchanged — crosstalk wraps only the main table; the drill-down uses none.

Dependency / blocker

Requires the interactive lt.js extension (sort/search/filter/paging as an opt-in add-on). Implementation plan lives in the lt repo (TODO.md). This forestly change is blocked until that extension is published.

Tasks

• Interactive lt extension available (see lt repo).
• Emit the AE listing once as a compact JSON global in ae_forestly().
• Switch details to a client-side JS() renderer calling the lt extension.
• Attach the lt (+ interactive extension) JS/CSS dependencies.
• Verify drill-down features (sort/search/filter/paging) and search semantics.
• Re-measure widget size and build time; update #147.

Refs #147, #157.