fix(test): drop image inside table cell instead of viewport center

The trailing separator paragraph added after tables caused the
synthetic drop at viewport center to land outside the cell. Target
the rendered `.superdoc-table-fragment` element so the drop
coordinates are inside the cell and getMaxContentSize() picks up the
cell context.

Author: luccas-harbour

tests/behavior/tests/tables/image-resize-in-cell.spec.ts

@@ -75,10 +75,10 @@ async function placeCursorInFirstTableCell(superdoc: SuperDocFixture): Promise<v
 
 /**
  * Dispatch a synthetic drag-drop carrying a canvas-generated PNG of the given
- * pixel dimensions at the viewport's centre.  Returns the number of files the
- * drop handler saw, mirroring the pattern in drag-drop-image-insertion.spec.ts.
+ * pixel dimensions inside the first table cell.  Returns the number of files
+ * the drop handler saw, mirroring the pattern in drag-drop-image-insertion.spec.ts.
  */
-async function dropOversizedImageAtViewportCentre(
+async function dropOversizedImageInFirstCell(
   superdoc: SuperDocFixture,
   imageWidthPx: number,
   imageHeightPx: number,
@@ -107,8 +107,11 @@ async function dropOversizedImageAtViewportCentre(
       dt.items.add(file);
       dt.effectAllowed = 'copy';
 
-      // Drop at the viewport centre.
-      const rect = host.getBoundingClientRect();
+      // Drop inside the rendered table fragment rather than the viewport
+      // centre, which may land in the trailing separator paragraph.
+      const tableFragment = host.querySelector('.superdoc-table-fragment');
+      const targetEl = tableFragment ?? host;
+      const rect = targetEl.getBoundingClientRect();
       const dropX = Math.round(rect.left + rect.width / 2);
       const dropY = Math.round(rect.top + rect.height / 2);
 
@@ -179,7 +182,7 @@ test('image dropped into a narrow table cell is constrained to the cell width',
   const IMAGE_WIDTH_PX = 1200;
   const IMAGE_HEIGHT_PX = 900;
 
-  const { droppedFileCount } = await dropOversizedImageAtViewportCentre(superdoc, IMAGE_WIDTH_PX, IMAGE_HEIGHT_PX);
+  const { droppedFileCount } = await dropOversizedImageInFirstCell(superdoc, IMAGE_WIDTH_PX, IMAGE_HEIGHT_PX);
 
   // If the drop handler did not receive any files the test environment does not
   // support synthetic drops; skip rather than fail.