fix(grid): preserve page size at query result limit

Closes #5965

apps/desktop/src/lib/dataGrid/__tests__/queryResultRowLimit.spec.ts

@@ -17,10 +17,17 @@ describe("query result row limits", () => {
 
   it("limits the final page and caps totals", () => {
     expect(limitQueryPagination({ limit: 100, offset: 950 }, 1_000)).toEqual({ limit: 50, offset: 950 });
-    expect(limitQueryPagination({ limit: 100, offset: 2_000 }, 1_000)).toEqual({ limit: 1, offset: 999 });
+    expect(limitQueryPagination({ limit: 100, offset: 2_000 }, 1_000)).toEqual({ limit: 100, offset: 900 });
     expect(queryResultLimitReached(950, 50, 1_000)).toBe(true);
     expect(queryResultLimitReached(900, 50, 1_000)).toBe(false);
     expect(capQueryResultTotal(1_500, 1_000)).toBe(1_000);
     expect(capQueryResultTotal(1_500, undefined)).toBe(1_500);
   });
+
+  it("keeps the configured page size when a last-page jump exceeds the row cap", () => {
+    expect(limitQueryPagination({ limit: 100, offset: 2_952_900 }, 100_000)).toEqual({ limit: 100, offset: 99_900 });
+    expect(limitQueryPagination({ limit: 100, offset: 2_952_900 }, undefined)).toEqual({ limit: 100, offset: 2_952_900 });
+    expect(limitQueryPagination({ limit: 100, offset: 2_000 }, 1_050)).toEqual({ limit: 50, offset: 1_000 });
+    expect(limitQueryPagination({ limit: 100, offset: 2_000 }, 50)).toEqual({ limit: 50, offset: 0 });
+  });
 });

apps/desktop/src/lib/dataGrid/queryResultRowLimit.ts

@@ -22,7 +22,8 @@ export function agentProtocolQueryResultMaxRows(maxRows: number | undefined): nu
 
 export function limitQueryPagination<T extends { limit: number; offset: number }>(pagination: T, maxRows: number | undefined): T {
   if (maxRows === undefined) return pagination;
-  const offset = Math.min(Math.max(0, pagination.offset), maxRows - 1);
+  const requestedOffset = Math.max(0, pagination.offset);
+  const offset = requestedOffset < maxRows ? requestedOffset : Math.floor((maxRows - 1) / pagination.limit) * pagination.limit;
   const remaining = maxRows - offset;
   return { ...pagination, limit: Math.min(pagination.limit, remaining), offset };
 }