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>

app/(app)/page.tsx

@@ -24,8 +24,8 @@ export default async function DashboardPage() {
     <div className="flex flex-col gap-8">
       <Card className="bp-glass overflow-hidden">
         <CardContent className="flex flex-col items-start gap-4 py-8">
-          <BrandMark size={40} className="bp-pulse rounded-[9px]" />
-          <h1 className="font-heading bp-gradient-text text-3xl font-semibold">Welcome back</h1>
+          <BrandMark size={48} animated className="rounded-[9px]" />
+          <h1 className="font-heading text-3xl font-semibold">Welcome back</h1>
           <p className="max-w-xl text-sm text-muted-foreground">
             Scan for nearby devices, take control, and record sessions to replay later - all running
             directly from your browser over Web Bluetooth.