style: real LED segment display font for kickoff time

- Added DSEG7 font (stadium scoreboard segment display)
- Kickoff time centered in card, no box, just glowing LED digits
- Gold color with double text-shadow glow for authentic look

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/index.css

@@ -2,6 +2,14 @@
    WM 2026 Tippspiel — Stadium Elite Design System
    ============================================================ */
 
+/* Stadium LED Segment Display Font */
+@font-face {
+  font-family: 'DSEG7';
+  src: url('https://cdn.jsdelivr.net/npm/dseg@0.46.0/fonts/DSEG7-Classic/DSEG7Classic-Regular.woff2') format('woff2');
+  font-weight: 400;
+  font-display: swap;
+}
+
 /* --- Dark Mode (Standard) --- */
 :root {
   --bg-deep:        #0A0E1A;