Restyle UI with a channel-strip console look and brand icon

Adds a pink/purple/blue SVG brand mark (favicon + header) and reworks
the visual language around the app's actual interaction - fader-driven
device control - via LED-style indicators, mono instrument readouts,
hairline-framed cards, console-tab nav, and an oscilloscope-style
session timeline. Leaves components/ui/* untouched, restyling only via
design tokens and the app's own composed components. Also fixes a
proxy.ts matcher gap that was gating /icon.svg behind auth.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W8WkFF5ppURBAB918593Eb

proxy.ts

@@ -22,5 +22,5 @@ export default async function proxy(req: NextRequest) {
 }
 
 export const config = {
-  matcher: ["/((?!_next/static|_next/image|favicon.ico|login|api/auth/login|api/health).*)"],
+  matcher: ["/((?!_next/static|_next/image|favicon.ico|icon.svg|login|api/auth/login|api/health).*)"],
 };