feat: the table sort gets its three keys and a sort type

Both dialogs offer three sort keys and let you pick the type; only the
first key was offered, and the type was always the detected one. A later
key decides only where the ones before tie, and the sort stays stable.

Alphanumeric is the plain collation ("10" before "2") — that is what
choosing it over the detected type is for, so the two collators differ in
`numeric`. Sorted numerically, a cell that is no number sorts last either
way, as an empty cell does in a spreadsheet.

docs/architecture/tables.md

@@ -17,7 +17,7 @@ Covers the `table*.ts` extensions in `src/lib/editor/extensions/` and the table-
 - **`tableHeaderRow.ts`** (`TableHeaderRow`) — "header row" as a **styling preset** (not the structural ODF header that repeats per page, by design): `toggleHeaderRowStyle` sets/clears a **light-grey fill (`HEADER_SHADE` `#F2F2F2`)** on the first row's cells; `isHeaderStyled(state, axis)` drives the toolbar toggle's active state. **A table carrying a table style owns these two areas through its Table Style Options instead**: there `toggleHeaderStyle`/`isHeaderStyled` read and write `headerRow`/`firstColumn` in the table's `tableLook` (delegating to `setTableLook`), so the toolbar button and the gallery's checkbox are one state and can't disagree. Both also read their label from the same key (`styles.regions.*`), so they can't drift apart in wording either — the button used to say "header column" where the checkbox said "first column". The fill is the *marker* and **round-trips natively** as `fo:background-color`, so the toggle state survives reopen with no `table:table-header-rows` (⇒ Word/LibreOffice don't repeat it). **Bold is presentational, exactly like a heading**: `tableCellBackground.ts` tags a header-shaded cell with `class="cell-header"` and `editor.css` renders `.cell-header` bold — so *all* its text is bold (existing, typed, pasted, IME) without storing marks, and it stays **editable** via the `fontWeight:'normal'` override (the `Toolbar.svelte` Bold button treats `isInHeaderCell` like a heading: toggles `setFontWeight('normal')`/`unsetFontWeight`). Export (`export/odt.ts`) **bakes** bold onto header-shaded cells' runs (`applyRuns(..., forceBold)`, skipping `fontWeight:'normal'` runs) so Word/LibreOffice match; import (`import/odt.ts`) converts those cells' runs with `boldByDefault` (bold run → no mark, normal run → `fontWeight:'normal'`), mirroring headings. `TableToolbar.svelte` exposes the toggle button.
 
 - **`tableFormula.ts`** (`TableFormula`) — a cell's **formula**, on the cell itself, which is where ODF puts it. The stored language is **Word's** (`SUM(ABOVE)`, `A1*2`, no leading `=`), the wider of the two; `utils/tableFormula.ts` holds the whole pure half — the tokenizer, the recursive-descent evaluator (`SUM PRODUCT AVERAGE MIN MAX COUNT ABS INT SIGN MOD ROUND`, ranges, Word's four directions, `+ - * / %` and parentheses) and the two translations. A **direction stops at the first cell holding no number**, a range does not. `evaluateTable` fills every formula cell in one pass, resolving a formula that reads another recursively behind a visited set, so a chain settles at once and a cycle yields 0 rather than looping. The `appendTransaction` recomputes on any doc change and writes the result as the cell's own text (keeping the first run's marks), **off the undo stack**; `editor.css` shades `td[data-formula]` the way both word processors shade a field, since typing over a result does not last. **ODF**: `applyCellFormulas` writes `table:formula="ooow:sum <A1:A3>"` (ABOVE resolved to the range it stands for — LibreOffice has no word for it) plus `office:value-type="float"`/`office:value`. The `ooow:` in that value is a **namespace prefix**: undeclared, LibreOffice reads it as part of the formula and prints "Expression is faulty", so `ensureOoowNamespace` declares it (probed both ways). **DOCX**: the cell's first paragraph becomes one `SimpleField` `=SUM(ABOVE)` with the result cached; import reads the instruction back off the cell. LibreOffice's own formula engine parses a cell's **text** in its locale regardless of number recognition (probed), which is why the editor formats a result in the document language.
-- **`tableSort.ts`** (`TableSort`) — LibreOffice's Table ▸ Sort / Word's Layout ▸ Sort on the one key both put first: `sortedRows` is pure (rows in, rows out), stable, orders numerically where both cells parse as numbers and by `Intl.Collator` otherwise, and keeps a header row in place. `canSortTable` refuses a table with a vertically merged cell — such a cell belongs to more than one row, so there are no rows to reorder. The command rebuilds the table node in one transaction.
+- **`tableSort.ts`** (`TableSort`) — LibreOffice's Table ▸ Sort / Word's Layout ▸ Sort with the three keys both offer, each with its own direction and sort type; a later key decides only where the ones before it tie, and column `-1` is the key that is off. `sortedRows` is pure (rows in, rows out) and stable, so rows alike in every key keep the order they were typed in. The type is `auto` (numeric where both cells parse as numbers, else the collation), `number` — where a cell that is no number sorts last either way, as an empty cell does in a spreadsheet — or `text`, which is the **plain** collation: "10" before "2" is the whole point of choosing it, so `sortCollators` builds one collator with `numeric: true` and one without. `canSortTable` refuses a table with a vertically merged cell — such a cell belongs to more than one row, so there are no rows to reorder. The command rebuilds the table node in one transaction.
 - **Number recognition** (`storage/tableOptions.svelte.ts`) — LibreOffice's Table ▸ Number Recognition, **off** by default there (its `Writer/Table/Input/NumberRecognition` schema default) and so here. On, a cell whose text reads as a number is rewritten in the document language's general number format when the **cursor leaves it**, which is where LibreOffice applies it. It is an app option, not part of the file — LibreOffice keeps it in its own registry too — so only its effect travels. `setTableLanguage` is pushed from `App.svelte`'s language effect; the exporters take the same locale from the `language` argument instead, staying store-free.
 - **`tableCellAlign.ts`** (`TableCellAlign`) — `verticalAlign` (`middle`/`bottom`, null = top, the ODF and Word default) on `tableCell`/`tableHeader`, rendered as the cell's CSS `vertical-align`. A callout table's label sits mid-cell with it, at the row's top without. Round-trips to ODF `style:vertical-align` (import via `StyleResolver.cellVerticalAlign`, export via odf-kit's `CellOptions.verticalAlign` — it mints one cell style per property set, so a differing cell gets its own) and DOCX `w:vAlign` (Word's `center` is our `middle`; `top`/`both` stay the default). Set from `TableToolbar.svelte`'s three buttons via `setCellAttribute`, which covers a whole `CellSelection`.
 - **`tableStyle.ts`** (`TableStyle`) — the **table style** family's editor half (model in `styles/tableStyles.ts`, see below): global attrs `tableStyle` on `table` (⇄ `data-table-style`) and `region` on `tableCell`/`tableHeader` (⇄ `data-region`, a space-separated region list). `setTableStyle(name|null)` writes the attr and **materializes** the style into the cells in one transaction — `paintTable` walks the `TableMap`, resolves each cell via `resolveTableCell` (merged cells by their top-left `findCell` box) and writes `backgroundColor`/the four border attrs/`region`, so **export, PDF and clipboard need no new code**. It only writes cells that differ, which makes it idempotent — the condition the re-band plugin depends on. That plugin (`appendTransaction`) repaints a styled table when its row/column **shape** changes (Word's re-banding); deliberately *not* on every transaction, or a manually shaded cell would be repainted away immediately. `refreshTableStyles()` repaints every styled table and is called from `Editor.svelte`'s document-stylesheet `$effect` — the choke point every registry change (edit, rename, reset, import) passes through. `activeTableStyle`/`cellRegionText` feed the gallery and the Bold button (a style's bold region behaves like a heading, see `tableHeaderRow.ts`). `TableView` sets `data-table-style` itself, since the node view bypasses `renderHTML`.