feat(app): UI parity with Pencil mockup — top bar, panel cards, sidebar/event-center polish

Top bar (breadcrumb + actions + account), rounded panel cards with active
accent + rich headers, sidebar count pills/collapsible groups/daemon footer,
preset chips + scrollback pill, Event Center tabs + external-notify footer,
JetBrains Mono + Inter via @fontsource, shared theme tokens. Backend-absent
pieces are mocked (search, zoom, uptime, channels) pending SP1–SP5.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/src/TerminalView.tsx

@@ -11,7 +11,7 @@ export function TerminalView({ surfaceId }: { surfaceId: string }) {
 
   useEffect(() => {
     if (!ref.current) return;
-    const term = new Terminal({ fontFamily: "monospace", fontSize: 13, convertEol: false });
+    const term = new Terminal({ fontFamily: "'JetBrains Mono Variable', 'JetBrains Mono', monospace", fontSize: 13, convertEol: false });
     try {
       term.loadAddon(new WebglAddon());
     } catch {