feat(runtime): 同步前端状态到 agent runtime

- 新增 snapshot 构造 helper 和 agent runtime store

- 同步 active tab、连接、库、schema、SQL、选中 SQL、表格选择和结果采样

- 补充 snapshot payload 组装测试

src/components/grid/DataGrid.vue

@@ -62,9 +62,17 @@ import type { QueryResult, ColumnInfo, DatabaseType } from "@/types/database";
 import * as api from "@/lib/api";
 import { buildTableSelectSql, quoteTableIdentifier } from "@/lib/tableSelectSql";
 import { isHiddenGridColumn, usesSyntheticRowIdKey } from "@/lib/tableEditing";
-import { formatGridSqlLiteral } from "@/lib/dataGridSql";
-import { matchesRowStatusFilter, type RowStatus, type RowStatusFilter } from "@/lib/gridRowStatus";
 import { displayCellValue, type CellValue } from "@/lib/cellValue";
+import { buildDataGridSaveStatements, formatGridSqlLiteral } from "@/lib/dataGridSql";
+import { formatMarkdownTable } from "@/lib/markdownTable";
+import { buildXlsxWorkbook } from "@/lib/xlsxExport";
+import {
+  matchesRowStatusFilter,
+  rowStatusFilterAfterAddingRow,
+  type RowStatus,
+  type RowStatusFilter,
+} from "@/lib/gridRowStatus";
+import { useAgentRuntimeStore } from "@/stores/agentRuntimeStore";
 
 import { useToast } from "@/composables/useToast";
 import { useDataGridExport } from "@/composables/useDataGridExport";
@@ -74,6 +82,7 @@ import { useDataGridEditor } from "@/composables/useDataGridEditor";
 
 const { t } = useI18n();
 const { toast } = useToast();
+const agentRuntimeStore = useAgentRuntimeStore();
 
 const props = defineProps<{
   result: QueryResult;
@@ -1090,6 +1099,22 @@ const activeCellDetail = computed(() => {
 const detailEditValue = ref("");
 const isEditingDetail = ref(false);
 
+watch(
+  selectedCells,
+  (data) => {
+    agentRuntimeStore.setSelection(
+      selectedCellCount.value > 0
+        ? {
+            type: "grid-cells",
+            range: selectedRange.value,
+            data,
+          }
+        : { type: "none" },
+    );
+  },
+  { deep: true },
+);
+
 function startDetailEdit() {
   const detail = activeCellDetail.value;
   if (!detail || !detail.isEditable) return;
@@ -1611,6 +1636,7 @@ watch(
 
 onUnmounted(() => {
   cleanupFrames();
+  agentRuntimeStore.setSelection({ type: "none" });
   onDdlResizeEnd();
   finishCellSelection();
   clearTimeout(_searchTimer);