style: move kickoff time to card header, better date header spacing

- Kickoff time now in header row: "Gruppe A · 04:00 Uhr · in 61 Tagen"
  instead of centered between flags (avoids visual misalignment)
- Date timeline headers: more top padding for balanced spacing
  between cards

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

frontend/src/pages/MatchesPage.module.css

@@ -89,7 +89,7 @@
   display: flex;
   align-items: center;
   gap: 12px;
-  padding: 4px 0;
+  padding: 12px 0 6px;
 }
 
 .dateLine {