fix(grid): reset scroll for replacement query results

Closes #5950

apps/desktop/src/lib/__tests__/tabs/tabPresentation.spec.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import { createPinia, setActivePinia } from "pinia";
 import { useConnectionStore } from "@/stores/connectionStore";
-import { connectionGroupDisplayName, executionSummaryItems, middleEllipsis, queryResultBaseSql, queryResultExecutionSql, resultSourceRange, statementExecutionMarkers, tabTooltipLines, tabularResultItems } from "@/lib/tabs/tabPresentation";
+import { connectionGroupDisplayName, executionSummaryItems, middleEllipsis, queryResultBaseSql, queryResultExecutionSql, resultGridCacheKey, resultGridInstanceKey, resultSourceRange, statementExecutionMarkers, tabTooltipLines, tabularResultItems } from "@/lib/tabs/tabPresentation";
 import { sqlTextFingerprint } from "@/lib/sql/sqlTextFingerprint";
 import type { ConnectionConfig, QueryTab } from "@/types/database";
 
@@ -133,6 +133,18 @@ describe("query result labels", () => {
   });
 });
 
+describe("query result grid identity", () => {
+  it("separates rerun payloads while retaining run and result-set identity", () => {
+    const first = queryTab({ activeResultRunId: "run-1", activeResultIndex: 2, resultGridRevision: "execution-1" });
+    const rerun = queryTab({ activeResultRunId: "run-1", activeResultIndex: 2, resultGridRevision: "execution-2" });
+
+    expect(resultGridInstanceKey(first)).toBe("tab-1-run-1-2-execution-1");
+    expect(resultGridInstanceKey(rerun)).not.toBe(resultGridInstanceKey(first));
+    expect(resultGridInstanceKey({ ...first, activeResultIndex: 1 })).toBe("tab-1-run-1-1-execution-1");
+    expect(resultGridCacheKey(rerun)).toBe(resultGridCacheKey(first));
+  });
+});
+
 describe("tab group presentation", () => {
   it("adds the full, live group path to tab tooltips", () => {
     const store = useConnectionStore();

apps/desktop/src/lib/tabs/tabPresentation.ts

@@ -349,6 +349,10 @@ export function resultGridCacheKey(tab: Pick<QueryTab, "id" | "activeResultRunId
   return `${tab.id}-${tab.activeResultRunId ?? "current"}-${tab.activeResultIndex ?? 0}`;
 }
 
+export function resultGridInstanceKey(tab: Pick<QueryTab, "id" | "activeResultRunId" | "activeResultIndex" | "resultGridRevision">): string {
+  return `${resultGridCacheKey(tab)}-${tab.resultGridRevision ?? "initial"}`;
+}
+
 export function nextExecutionSummaryView(currentView: OutputView, canShowResult: boolean): OutputView {
   if (currentView === "summary" && canShowResult) return "result";
   return "summary";