Add animated glass background, breadcrumbs, and brand mark polish

Cards now sit on an animated signature-gradient background and use a
translucent, blurred bp-glass surface so it shines through; extended
bp-glass to every stat surface on the Stats page and to its tab switcher.
Adds a Breadcrumbs component below the header on all app pages.

Also: drop the gradient text fill from the wordmark/heading, animate the
BrandMark's heart and curve on the dashboard hero instead of a plain pulse
ring, recenter the heart/curve artwork in icon.svg and BrandMark, close the
mobile nav menu on link click, remove the redundant "back to recordings"
button, and match the "Start session"/"Scan for devices" button sizes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

components/stats/SessionsSummaryCards.tsx

@@ -40,9 +40,11 @@ export function SessionsSummaryCards({ summary }: { summary: SessionsSummary })
           </CardContent>
         </Card>
       </div>
-      <p className="text-sm text-muted-foreground">
-        {liveCount} live · {replayCount} replay
-      </p>
+      <Card className="bp-glass">
+        <CardContent className="py-3 text-sm text-muted-foreground">
+          {liveCount} live · {replayCount} replay
+        </CardContent>
+      </Card>
       {summary.durationPerDevice.length > 0 && (
         <Card className="bp-glass">
           <CardHeader>