fix(Table): include expanded row height when measuring virtualized rows

When a row renders an expanded sibling `<tr>` (`row.getIsExpanded()`),
the virtualizer measures only the primary `<tr>` and misses the
expansion, causing `getTotalSize()` to under-report and the footer
`translateY` offset to drift.

Provide a default `measureElement` that, when the measured element has
`data-expanded="true"`, also adds the immediate next `<tr>` sibling's
height. A user-supplied `measureElement` still takes precedence for the
primary row — the expansion sum is layered on top.

Addresses CodeRabbit review feedback on nuxt#6379.

Author: claylevering

src/runtime/components/Table.vue

@@ -439,6 +439,17 @@ const virtualizer = !!props.virtualize && useVirtualizer({
   estimateSize: (index: number) => {
     const estimate = virtualizerProps.value.estimateSize
     return typeof estimate === 'function' ? estimate(index) : estimate
+  },
+  measureElement: (el, entry, instance) => {
+    const userMeasure = virtualizerProps.value.measureElement
+    const base = userMeasure
+      ? userMeasure(el, entry, instance)
+      : Math.round(entry?.borderBoxSize?.[0]?.blockSize ?? (el as HTMLElement).offsetHeight)
+    if ((el as Element).getAttribute('data-expanded') === 'true') {
+      const next = (el as Element).nextElementSibling as HTMLElement | null
+      if (next && next.tagName === 'TR') return base + next.offsetHeight
+    }
+    return base
   }
 })