`GridCache::row_labels`/`col_labels` were `Vec<String>` built by
`GridLayout::row_label`, which slash-joins a multi-level tuple — the exact
rendering `two_row_categories_produce_cross_product_labels` asserts must not
appear. So the protocol carried a form of the labels the TUI itself
considered wrong, and `improvise-wasm-client/src/render.rs` drew precisely
that form: the browser showed `Food/Alice` where the TUI showed two header
columns, with no groups and no collapse indicators (gotcha 44).
Both fields become one `AxisFrame` per axis, carrying the five facts gotcha
44 enumerates: the categories (hence the header levels), the label *tuples*
and the inline group headers, the group a position sits in, and each group's
collapse state. `record_col` stays off — session-local, keys pending drill
edits, correct to keep off.
It is one type and not a `row_levels` beside `row_labels`, because two
answers to "what are the labels" is the disease (improvise-edp). The rules
that used to be written twice are methods on it and are now called from both
front ends: `shows_level` (repeat suppression, improvise-jjx's fix),
`group_of`, `body_from`, and `header_widths` — the row-header width rule,
which existed twice already, inline in `render_grid` and again in
`viewport::compute_row_header_width` (improvise-1125).
`GridWidget` loses its `&View`: nothing in it reads the view any more.
Evidence. `the_whole_frame_is_unchanged` — the exact-buffer characterization
over a grid with row groups, column groups, a page axis, multi-level headers
and a total row — passes byte for byte, so the TUI is unchanged. The new
`tests/grid_frame_agreement.rs` drives the widget into a ratatui buffer and
the browser client through a `Snapshot` of the *same* cache, and compares
what each draws; re-introducing the slash-join on either side was injected
and watched to fail before the test was kept.
`tests/web_demo_model.rs::the_web_demo_has_one_category_per_visible_axis` is
deleted: it guarded the gap this closes, and a consolidation that keeps its
compatibility test is unfinished.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Edward Langley
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