fix(ui+game): responsive profile bar, auto-wave toggle, and stats on early exit

Profile bar on phones:
- With the new Statistik/Admin chips the bar overflowed the viewport on
  small screens. It now wraps (flex-wrap + max-width) and compacts its
  paddings, fonts and chip sizes below 560px

Auto-wave (🔁 button in the HUD controls):
- New persistent toggle (localStorage) that starts the next wave on its
  own ~0.4s after intermission begins, collecting the full early-call
  bonus without pressing the wave button every round
- Toggling it on during an active intermission starts the wave
  immediately; works in solo and multiplayer (uses the same action path
  as the manual button); active state shows green

Stats are now saved when leaving via the menu:
- Previously only victory/defeat recorded a result — exiting a running
  game via "🚪 Zurück zum Hauptmenü" or the pause menu discarded the
  whole run, which is why endless-mode progress beyond wave 20 never
  showed up in the stats
- engine.abandon() records best score, stats and crystals (counted as a
  defeat) whenever a solo game is left mid-run; no-ops when no game is
  running or the result was already reported, so no double counting

Verified in the browser (390x844, admin account): profile bar wraps
compactly; 🔁 auto-started wave 1 during intermission without manual
click; exiting mid-wave recorded the run (💎 2, 1 Runde, beste Welle 1).
Build clean, 54/54 tests green.

src/components/UserProfileBar.vue

@@ -49,7 +49,9 @@ async function doLogout(): Promise<void> {
 .profile-bar {
   display: flex;
   align-items: center;
+  flex-wrap: wrap;
   gap: 8px;
+  max-width: 100%;
   background: var(--panel);
   border: 1px solid var(--panel-border);
   border-radius: 12px;
@@ -79,6 +81,25 @@ async function doLogout(): Promise<void> {
   padding: 5px 10px;
   cursor: pointer;
 }
+
+/* Phones: chips wrap into compact rows instead of overflowing */
+@media (max-width: 560px) {
+  .profile-bar {
+    gap: 5px;
+    padding: 5px 8px;
+  }
+  .crystals {
+    font-size: 13px;
+  }
+  .name {
+    font-size: 11.5px;
+    max-width: 92px;
+  }
+  .chip {
+    font-size: 11px;
+    padding: 4px 8px;
+  }
+}
 .chip:hover {
   border-color: var(--accent);
 }