feat(chart): Auto-execute chart on chart explorer page load (#1961)

## Summary

Updates the chart explorer page so that the chart query is executed automatically once on page load instead of waiting for the user to click the run button.

The motivation is external tools that translate queries from other systems into HyperDX chart configs and deeplink the user into the `/chart` page. Today the user lands on a fully-populated form but still has to click once to see results; with this change the chart renders immediately.

The form gains an `autoRun` prop. When true, a latched effect calls `onSubmit()` exactly once after the source data has loaded, so form validation has the table metadata it needs.

### How to test locally or on Vercel

1. `yarn dev` in `packages/app`
2. Open `/chart?config=%7B%22name%22%3A%22%22%2C%22select%22%3A%5B%7B%22aggFn%22%3A%22count%22%2C%22aggCondition%22%3A%22%22%2C%22aggConditionLanguage%22%3A%22sql%22%2C%22valueExpression%22%3A%22%22%7D%5D%2C%22where%22%3A%22%22%2C%22whereLanguage%22%3A%22sql%22%2C%22displayType%22%3A%22line%22%2C%22granularity%22%3A%22auto%22%2C%22source%22%3A%22<your-source-id>%22%7D` — replace `<your-source-id>` with a real source id from your instance
3. The chart should render results without clicking the run button

Author: sanjams2

.changeset/chart-explorer-auto-run.md

@@ -0,0 +1,5 @@
+---
+"@hyperdx/app": patch
+---
+
+feat: Chart Explorer now auto-executes the chart on load when a valid source is configured. Deeplinks render results without requiring a manual click.

packages/app/src/DBChartPage.tsx

@@ -253,6 +253,7 @@ function DBChartExplorerPage() {
         onTimeRangeSearch={onSearch}
         onTimeRangeSelect={onTimeRangeSelect}
         submitRef={submitRef}
+        autoRun
       />
     </Box>
   );

packages/app/src/components/DBEditTimeChartForm.tsx

@@ -546,6 +546,7 @@ export default function EditTimeChartForm({
   'data-testid': dataTestId,
   submitRef,
   isDashboardForm = false,
+  autoRun = false,
 }: {
   dashboardId?: string;
   chartConfig: SavedChartConfig;
@@ -562,6 +563,7 @@ export default function EditTimeChartForm({
   'data-testid'?: string;
   submitRef?: React.MutableRefObject<(() => void) | undefined>;
   isDashboardForm?: boolean;
+  autoRun?: boolean;
 }) {
   const formValue: ChartEditorFormState = useMemo(
     () => convertSavedChartConfigToFormState(chartConfig),
@@ -827,6 +829,14 @@ export default function EditTimeChartForm({
     }
   }, [onSubmit, submitRef]);
 
+  const autoRunFired = useRef(false);
+  useEffect(() => {
+    if (autoRun && !autoRunFired.current && tableSource) {
+      autoRunFired.current = true;
+      onSubmit(true);
+    }
+  }, [autoRun, tableSource, onSubmit]);
+
   const handleSave = useCallback(
     (form: ChartEditorFormState) => {
       const errors = validateChartForm(form, tableSource, setError);