Remove stats tab switcher, drop duration-per-device, show devices inline

Sessions and Devices no longer live behind a Tabs switcher on the stats
page - both sections render directly, one after the other. Also drops
the "Duration per device" list from the sessions summary cards since
DeviceUsageTable already shows per-device active time in more detail.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WzyfRyA7h5rs5SCAahLAWd

app/(app)/stats/page.tsx

@@ -1,5 +1,4 @@
 import type { Metadata } from "next";
-import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { SessionsSummaryCards } from "@/components/stats/SessionsSummaryCards";
 import { DeviceUsageTable } from "@/components/stats/DeviceUsageTable";
 import { getDeviceCommandCounts, getDeviceUsageStats, getSessionsSummary } from "@/lib/db/queries/stats";
@@ -24,18 +23,8 @@ export default async function StatsPage() {
         <p className="text-sm text-muted-foreground">Usage across sessions and devices.</p>
       </div>
 
-      <Tabs defaultValue="sessions">
-        <TabsList className="bp-glass">
-          <TabsTrigger value="sessions">Sessions</TabsTrigger>
-          <TabsTrigger value="devices">Devices</TabsTrigger>
-        </TabsList>
-        <TabsContent value="sessions" className="pt-4">
-          <SessionsSummaryCards summary={sessionsSummary} />
-        </TabsContent>
-        <TabsContent value="devices" className="pt-4">
-          <DeviceUsageTable devices={devices} />
-        </TabsContent>
-      </Tabs>
+      <SessionsSummaryCards summary={sessionsSummary} />
+      <DeviceUsageTable devices={devices} />
     </div>
   );
 }