fix: close browser session lifecycle gaps

apps/web/src/App.tsx

@@ -14,6 +14,7 @@ import { HarnessClientStore } from "./store/harness-client-store.js";
 
 type AppStore = HarnessRuntimeStore & {
   start(): Promise<void>;
+  dispose?: () => Promise<void>;
   getModelConfig(): Promise<{ modelConfig: ModelView }>;
   putModelConfig?: (input: ModelConnectionInput) => Promise<{ modelConfig: ModelView }>;
   testModelConfig?: () => Promise<{ status: "ok" | "deferred"; message: string }>;
@@ -87,7 +88,17 @@ export function App({ store: suppliedStore, autoStart = true, modelConfigured: s
           modelLabel: model.modelId ?? "No model",
           supportsImages: model.supportsImages ?? false,
           onOpenSettings: () => setSettingsOpen(true),
-          onReset: () => window.location.reload(),
+          onReset: () => {
+            if (store.dispose === undefined) {
+              window.location.reload();
+              return;
+            }
+            void store.dispose()
+              .then(() => store.start())
+              .then(() => store.getModelConfig())
+              .then((response) => setModel(response.modelConfig))
+              .catch(() => undefined);
+          },
         }}
         skills={<SkillsPanel skills={snapshot.skills} />}
         chat={<Thread