fix: restore overview workstream mode reactivity

dashboard/src/index.md

@@ -252,16 +252,20 @@ _modeSelect.value = _savedChartMode;
 _modeSelect.addEventListener("input", () => {
   globalThis.__stateHubOverviewChartMode = _modeSelect.value;
 });
+_modeSelect.addEventListener("change", () => {
+  globalThis.__stateHubOverviewChartMode = _modeSelect.value;
+});
 
 // view() is the idiomatic Observable Framework reactive input:
 // it displays the element AND returns a reactive value that re-runs dependent blocks.
 const _chartMode = _modeValue(view(_modeSelect));
-const _chartWsFiltered = _workstreamsForMode(_chartMode, wsAll);
 ```
 
 ```js
 import * as Plot from "npm:@observablehq/plot";
 
+const _chartWsFiltered = _workstreamsForMode(_chartMode, wsAll);
+
 // Sort by domain, then repository, then most recently updated workstream.
 // The axis labels show each domain/repo group once.
 const chartWs = [..._chartWsFiltered].sort((a, b) => {