fix: dropping a fully covered table row shrinks the spans across it

A row holding only covered cells cannot exist in the editor and was
dropped on ODT import, but every rowspan reaching over it kept its
full count, leaving an inconsistent grid. Spans now shrink by the
dropped rows they covered.

src/lib/import/odt.ts

@@ -2513,8 +2513,14 @@ function convertTable(el: Element, ctx: Ctx): Node | null {
   const weights = columnWeights(el, ctx.resolver);
 
   const rows: Node[] = [];
+  // Source-row bookkeeping: a row of only covered cells is dropped (the editor cannot
+  // hold a cell-less row), so every span reaching over it must shrink by one.
+  const placed: { attrs: Record<string, unknown>; row: number; span: number }[] = [];
+  const dropped: number[] = [];
+  let srcRow = 0;
   let cellPad: CellPadding | null | undefined;
   const addRow = (rowEl: Element, header: boolean) => {
+    const rowIdx = srcRow++;
     const cells: Node[] = [];
     let colIndex = 0;
     for (const cellEl of Array.from(rowEl.children)) {
@@ -2559,6 +2565,7 @@ function convertTable(el: Element, ctx: Ctx): Node | null {
       const cellFormat = formula ? cellNumberFormat(cellEl, ctx) : null;
       for (let r = 0; r < repeated; r++) {
         const attrs: Record<string, unknown> = { colspan, rowspan, ...borders };
+        if (rowspan > 1) placed.push({ attrs, row: rowIdx, span: rowspan });
         if (formula) attrs.formula = formula;
         if (cellFormat) attrs.cellFormat = cellFormat;
         if (ownPad) attrs.cellPadding = ownPad;
@@ -2573,7 +2580,7 @@ function convertTable(el: Element, ctx: Ctx): Node | null {
         colIndex += colspan;
       }
     }
-    if (cells.length === 0) return;
+    if (cells.length === 0) { dropped.push(rowIdx); return; }
 
     const row: Node = { type: 'tableRow', content: cells };
     const heightCm = ctx.resolver.rowMinHeightCm(rowEl.getAttributeNS(NS.table, 'style-name'));
@@ -2593,6 +2600,10 @@ function convertTable(el: Element, ctx: Ctx): Node | null {
   }
 
   if (rows.length === 0) return null;
+  if (dropped.length) for (const p of placed) {
+    const cut = dropped.filter((d) => d > p.row && d < p.row + p.span).length;
+    if (cut) p.attrs.rowspan = p.span - cut;
+  }
   // The named table style behind the automatic one. ODF stores no banding, so only the
   // name comes back — the look rides on the cell attrs above, and the editor re-derives
   // the regions from the registry (refreshTableStyles).